K-On!'s Yui Hirasawa. Her guitar becomes "Gitah", Tsumugi becomes "Mugi-chan", Ritsu becomes "Ricchan", and Azusa becomes "Azu-nyan". Later, Mio's bass becomes "Elizabeth". Also, in the "extra" episode, she calls her pair of gloves "Tebukuro-chan".
When her sister (Ui) impersonated her, her friends first became suspicious because Ui got all the nicknames wrong. Sawako saw through it immediately, though, because she instantly noticed the change in bust size... which is partially excused by the fact that she is the band's costume designer/creator... but still.
Yachiru Kusajishi from Bleach, the most infamous of her nicknames being "Ken-chan" (Kenny in the dub) to her giant, bloodthirsty behemoth of a captain. Although it's not assured what she will call you or even if her nickname will be consistent, but she will give anyone, and everyone a nickname of some sort. Always.
Fai from Tsubasa Reservoir Chronicle starts calling Grumpy Bear Kurogane various nicknames (often some variant of "Kuro-pon" or "Kuro-rin") that becomes a running gag. When Fai stops using the nicknames it's obvious that something has gone very, very wrong, and likewise the next time he uses one everyone is relieved that he's back to normal. Fay openly states that he had never used nicknames for anyone before Kurogane. Hint hint. Kurogane might also apply: Tomoyo is the only person he ever calls by their real name. Fay is "the mage", Sakura "the princess", Syaoran "the kid", Mokona "the meat bun" and Yuuko is "the witch".
Gigalt from Planetes cannot remember a name, and makes up a nickname for each character he interacts with, but it must have meaning for him. He cannot seem to remember names otherwise. He gave Hachi his nickname, called Ai 'Angel', etc. The reason he couldn't come up with a nickname for Hakim was because Hakim was hiding his true self as a deep cover SDF mole, even under Gigalt's tutelage.
The titular character of Naruto almost never refers to certain people by their names, instead using nicknames he has chosen for them, often against their wishes. For example, Tsunade is "Grandma Tsunade" or just "Grandma," Jiraiya is "Pervy Sage," and Killer B is "Shades-Wearing Pops" or "Octopops." Depending on who it is, the nicknames can be insulting, affectionate, or both.
Ritchie from the Pokémon anime, to his Pokemon team; each and every one is nicknamed, which is rare for the anime.
Gold from the Pokémon Special manga has a nickname for everyone except his rival, Silver. Examples include Strict/Serious Girl (Crystal), Prissy Boy (Ruby) and Wild Girl (Sapphire).
Most characters nickname their Pokémon in PokeSpe, for that matter. Though some are more original than others.
Suzuna the cheerleading captain of the Deimon Devilbats in Eyeshield 21 nicknames most of the team apart from Sena and Monta. She once got an omake page listing all her nicknames for them. She even took to calling the pointy-eared Youichi Hiruma "You-nii" ("Elf-bro").
Hiruma himself gives everyone a caring, sweet and kind Fucking Nickname.
One of the incidental characters (who gave Eyeshield 21 the nickname "E.S.") is later revealed to make up nicknames for everything all the time.
Agon himself has a nickname for almost everyone. Short Trash (Sena), Slimy Trash (Hiruma), Fat Pig/Fat Trash (Kurita), Garbage Brothers (Ha-Ha Bros), and Unko-Chan (Unsui) are the more memorable ones. Ikkyu seems to be the only one Agon calls by name.
Eve Neuschwanstein of NEEDLESS, due to her atrocious memory for names.
Izaya and Erika from Durarara!! are both prone to this, though for different reasons. Izaya tends to throw out infantilizing nicknames for old highschool "friends" (i.e. Shizu-chan and Dotachin for Shizuo and Kadota) out of disrespect for them. Erika tends to give everyone equally silly nicknames (as well as commandeer Izaya's) because she's a raging Fangirl and thinks they're cute.
Luigi Yoshida in Giant Killing not only nicknames others around him but apparently made the rest of the team call him "The Prince" (he also has another nickname, Gino). Tatsumi the team manager refuses to call him by any of his nicknames until he proves himself.
Sanosuke Sagara has shades of this since he barely ever calls anyone by their given name. He calls Kaoru "Jou-chan" (translated to "Missy" in English), Megumi "kitsune" ("vixen" in English) most often, but anyone else he meets is probably not going to get called by their real name and will instead be referred to by whatever outstanding feature Sano notices (in Saito Hajime's case, his slicked-back hair with a few bangs in the front led Sanosuke to dub him something equally insulting). Humorously, Megumi calls him "tori-atama" (translated roughly to "birdhead" or "roosterhead") as retaliation. He also managed to seriously anger a minor villain by calling him "broom-head", a reference to his upswept blond hair.
Kafuka Fuura from Sayonara, Zetsubou-Sensei has her own naming conventions as an insanely positive cloud-cuckoolander; upon interrupting her future teacher's efforts at 'making himself taller' (read: suicide attempt) she nicknamed him 'Pink Supervisor' after the tree he was trying to hang himself from, 'Pink CEO', which she named on the spot. She constantly comes up with more positive names for things e.g. 'treasure chests for the homeless' (bins) and 'deep love' (stalking).
In One Piece you have to earn the right for Luffy to remember your real name. Especially apparent with Hancock, who remained Hammock while Luffy was still mad at her for turning her loving subjects to stone, and only became Hancock when she regained Luffy's respect by going the extra mile by facing her fears of going to fight for the marines so she could help him save Ace. But even if Luffy likes you, you might end up with one of his affectionate nicknames, like Cricket the "diamond head guy" or Inazuma "Crab-chan".
However, if someone makes Luffy hate them enough, he will also remembers that person's name. Crocodile is one of the few individuals that Luffy calls by name who he despise and still holds a grudge against. When fighting Arlong, he also called him by his name without ever given him a nickname. He also calls all three of the admirals by their official nicknames, despite only really 'liking' Aokiji.
Robin is the nicknamer within the Straw Hat crew. She is fond of using Hey, You! and if she does go by name, it's by a simple nickname such as Long-nose-kun (Usopp), Swordsman-san (Zoro) or Cook-san (Sanji). The only crewmate she calls by name is Luffy and that was after she had finally found her place with the Straw Hats.
After the events at Enies Lobby, during which she realized that her crew would never betray her and were ready to go to hell and back to save her, she does gradually stop using nicknames.
Similarily, Franky also used to nickname his crewmates, calling them by attribute-related monikers instead of their actual names; the only exception being Robin, who he referred to by her full name. He eventually stops using nicknames (And switches to First Name Basis for Robin) as he gets closer to his crewmates.
Rintaro of Steins;Gate has nicknames for everyone. Itaru is "Daru", Moeka is "Shining Finger", and Kurisu has a truckload of nicknames, including "Christina" ("There's no '-tina'!"), "The Zombie" and "Celeb-17".
Sakuragi Hanamichi in Slam Dunk has a tendency of giving nicknames to some of his rivals: Akagi is "Gori" (short for 'Gorilla'), Uozumi is "Boss Monkey", Hanagata is "Glasses", and Nobunaga is "Wild Monkey" (and in turn, he's called "Red-haired Monkey" by Nobunaga)
Riko's father, Kagetora, from Kuroko No Basuke. Kise may count to a lesser extent, as he adds "cchi" to the end of the names of people he's acknowledged, whether they want him to or not.
Rebecca Miyamoto, the teacher from Pani Poni Dash! starts out calling all of her students by stereotypical nicknames (Bookworm, Cowlick, Boring Girl) because she can't be bothered trying to learn them. Eventually she does learn everyone's names, though.
Alice from Pandora Hearts comes up with a nickname for nearly every person she meets. To name a few, Gil is "Seaweed-Head," Break is "the clown," Rufus Barma is "Ahoge," Leo is "Shaggy Glasses," etc.
In Hidan no Aria, Riko calls Kinji "Kii-kun", Shirayuki "Yuki-chan", and herself "Rikorin" (or "Rikko-Rikorin" when she's really cheerful). She also calls Aria "Arian'ya" or "'Olmes" (like in French) depending on her mood.
Ra's Al-Ghul calls Batman "Detective", and on the occasions he's faced Superman, he calls him "Icon" or "The Alien". More recently, he's taken to also calling Tim Drake "Detective" after Tim proved his skills against Ra's and earned his respect.
In Sgt. Rock, nicknames for all the members is the tradition of Easy Company, with Rock personally doling them out (And being the sole exception to the rule). This is explained as a coping mechanism for the unpleasant things they might have to do in the service of their duties in war, and to soften the blow should any of them die. And they do.
Apparently Truth in Television, as this is reportedly not an uncommon practice in times of war. It's also appeared in war fiction quite a few times, so maybe the 'Nicknamer sergeant' should be considered a subtrope of the Nicknamer.
The Taskmaster has a long history of obnoxious pet names for all, going right back to his first appearance in the 1980s. And considering how many superheroes and villains he's interacted with, that's a lot of pet names. This trait comes and goes a bit with later writers and how well they keep to his original "snarky Bronx thug" persona, though.
Ben Grimm of the Fantastic Four, usually of the semi-derogatory kind: "Stretch", "Stretcho", "Rubber Head", "Big Brains", "Professor", "Doc", "High Pockets", etc for Reed; "Match-head" "Matchstick", "Bic-head", "Flame-Brain", "Hothead", "Sparky", "Firefly", etc for Johnny. He always calls Sue by the pet names "Suzy" or "Suzy-Q" however, possibly since she's the one who pisses him off the least.
Spider-Man is fond of shortening the names of his allies and villians. The Green Goblin and the Hobgoblin are Gobby and Hobby, Doctor Octopus is Doc Ock, Daredevil is DD or Hornhead, he's borrowed Matchstick from Ben Grimm for The Human Torch etc. In at least one adapation, insulting Max Dillion with the name "Electro" is what inspires him to use it as his villian name.
The four attract their share of nicknames as well.
The Elemental Chess Trilogy gives this role to Edward Elric, but in a limited capacity. He only does it to Roy Mustang, for whom he never uses the same nickname twice, calling him things like "General Chess Fiend," "General Skirtchaser," and "the walking cigarette lighter." On the rare occasion he uses the man's real name, it's a pretty serious situation.
JoJo Bates, the protagonist of The Gift even makes a nickname for her therapist.
In Winter War, Madarame Ikkaku starts giving nicknames in imitation of his missing vice-captain. For example, he calls Momo "Peaches" and Grimmjow "Boy Blue".
During one of the chapter openings, Terriermon lists every single one of the nicknames in order to make up for the last chapter being rather short.
In Another Kind Of Magic, Trixie has a nickname for each of her friends ('Hayseed', 'Diva', 'Hummingbird', 'Wet Blanket', 'Neon Sign') while her best friend Twilight labours under several. She only does it out of affection, however, and genuinely love them all. This does not mean Twilight isn't horrified when Trixie refers to their mutual mentor, Celestia, as 'Princess Overrated'. (And later refers to the royal sisters as 'Bright Light' and 'Night Light'.)
To be exact, Captain America is "Old Man" (who is technically 70+ years old), as well as "Capsicle" (due to his status as a Human Popsicle). Thor is "Point Break" (because of his long blond hair and beard, which look similar to Patrick Swayze in that movie). Hawkeye is "Legolas" (being an archer). Loki is "Reindeer Games" (due to the helmet) and "Rock of Ages" (due to his regalia). Loki's staff is "the Glowstick of Destiny" (which glows and mind controls people).
Brian, the floor manager in Extract, refers to almost all of his subordinates as "Dinkus", with the one exception being a character he calls "Forklift Dinkus" or "Boy Genius".
Gunnery Sgt. Hartman from Full Metal Jacket gives each of his Marines a nickname in bootcamp. Not only does this stick throughout the movie, but for many of the characters, it's the only name the audience learns.
Night at the Museum: Security guard Gus does this repeatedly with Larry, giving him numerous derogatory nicknames(one for each time he addresses him, really) most with a bent towards food items like "Cupcake", "Hot Dog" and "Butterscotch", and also goes off the rails with things like "Snack Shack" and "Lunch Box", etc. He also calls him "Hopscotch".
Jenson in Day of the Animals, jackass that he is, refers to everyone in the backpacking group by the nicknames he has given to them, "Hot Shot" for Buckner, "Kemosabe" for Santee, and so on.
Sir Kay in Arthurian legend appears to be unpopular with the court partially because of this (and his tendency to make fun of whoever he does it to). When Sir Gareth comes to court in disguise and refuses to give his name, Kay calls him Beaumains, badnote Gendered names are difficult, aren't they? French for "Pretty Hands;" when Brunor the Black arrives at court wearing the coat his father was murdered in, he becomes far better known by what Kay calls him: Sir La Cote Male Tailenote La cotte mal taillée (The knight of the ill-fitting coat); and he refers to Sagramore as "Morte Jeune" (young corpse) on occasion due to his epilepsy-like fits. In T.H. White's The Once and Future King, he is the one that gave Arthur the nickname Wart because it rhymes with Art, or at least did in the accent of the age. White omits the nicknaming habit but does make Sir Kay a semi-sympathetic Jerk Ass.
Simon Darcourt, a repeat character in Christopher Brookmyre novels, makes his mark early by never calling anyone by their real name if he can substitute one of his own ("But you just are [insert nickname], don't you see?"). Div, the designated ditz in their circle of friends, even gets to call him on it:
"He thinks he's Jesus the noo. "Simon, I dub thee 'Peter'".
The Dresden Files: Harry Dresden has been known to nickname people whose actual names he doesn't know, so we get things like "Spinyboy," "Turtleneck," and "Eyebrow." But the most awesome nicknaming he ever did was when he decided that "Knights of the Order of the Blackened Denarius" was too dignified and started referring to a bunch of centuries-old demon-possessed psychos and their terrifying leader Nicodemus as "Nicky and The Nickelheads."
This tendency turns out remarkably well for Harry on several occasions. Thanks to the inherent power of names, there are at least three instances in the books in which Harry gives a very powerful magical entity a nickname and, in doing so, influences it for the better. The entities in question are a spirit of intellect with vast knowledge of magic and lore ("Bob the Skull"), the Archive of the entire collected knowledge of mankind ("Ivy") and the psychic imprint or "shadow" of a fallen angel named Lasciel ("Lash"). Lash is an especially noteworthy case in that by giving her a name of her own, Harry gave her an identity separate from Lasciel and introduced her to the concept of free will. This is questionable about Ivy. It seems to be good, but, Luccio does make some good, if absolutely heartless, points about why The Archive isn't supposed to do that.
"Shagnasty" the skinwalker. Justified, since it feeds on fear and therefore calling it something that isn't silly will just make it stronger.
He also does it with monsters when he doesn't like their real names. In Summer Knight, he decided that "plant monster" sound stupid and started calling it a "chlorofiend" instead; the Ik'k'uox in Changes became "The Ick" in the interests of pronounceability, and Esteban and Esmerelda, a pair of feared Red Court vampire assassins, become "the Eebs".
And in Blood Rites, he abbreviates "Black Court vampires" to "blampires" when signalling with his staff; Ebenezar initially thinks he's cocked up the Morse code.
Ghost Story has "Captain Turtleneck" and "The Big Hoods." Later he calls Uriel, the freaking archangel and God's own spymaster, "Uri". Uriel isn't pleased (at all) about having such a significant part of his name left off, but subsequently accepts "Mr. Sunshine" as an alternative.* For those not fluent in classical Hebrew, "Uriel" means "God is my light", and the "el" part that Harry so carelessly omitted translates into "God". On the other hand, "Uriel" can be very, very loosely translated as "Mr. Sunshine", which is probably why the Archangel accepted it.
In the tabletop sourcebook, the entry for a character known only by nickname is accompanied by a rueful note about how a detective should probably be better at learning people's names.
As befitting the fact that they're homages to the same tradition, Mack, of The Automatic Detective, enjoys nicknaming all the mooks he interacts with in much the same manner as Dresden. Luckily for him, he lives in a world full of mutants and aliens, making his job easier, nicknames such as "Dome Head", "Hairlip" and "Jellyfish" being entirely accurate descriptions.
In Terry Pratchett's Johnny Maxwell Trilogy, Johnny is the official nickname generator for his friends. In the second book it takes him a moment to remember that Bigmac's social worker would know him as Simon.
Ser Alliser Thorne in A Song of Ice and Fire is the member of the Night's Watch in charge of training new recruits. He gives insulting nicknames to his recruits, for instance "Ser Piggy" for fat Samwell Tarly and "Lord Snow" for highborn bastard Jon Snow.
"Toad. Stone Head. Aurochs. Lover. Pimple. Monkey. Ser Loon. (...) And the Bastard."
In the fifth book, Jon as Lord Commander is officially addressed as "Lord Snow"
Stannis Baratheon, despite having absolutely no sense of humor, appears to be this, giving other characters such charming names as 'Lord Too-Fat-To-Sit-a-Horse' and 'Ser Stupid'.
Aaron Allston's Star Wars Expanded Universe short story The Pengalan Tradeoff has Joram Kithe, an accountant sent to gauge the skills of clone troopers, finding himself cut off in enemy territory with them. Annoyed with their lack of names and the inconvenience of using their numbers, he gives them all nicknames - Tooth, Mapper, Digger, Hash - based on little differences, which he encourages in order to make it easier for him to tell them apart. In doing this he damages their absolute unity, making them considerably less interchangeable, but also encouraging them to think more creatively and humanizing them, for himself and the readers.
In 101 Ways to Bug Your Parents, the cool kid in the main character's class gave the entire class nicknames. This included the teacher who was known as "The Scribbler". The main character (Steve) is known as "Sneeze", due to his asthma. His best friend (Hector) is called "Hiccup", because of, well, his hiccups.
In the Sammy Keyes series, Sammy does this to absolutely everyone she meets before she knows their real names. If she doesn't particularly like them, though, the nickname tends to stick forever. Two of her nicknames ("Snake Eyes", "Psycho Kitty Queen") even became titles of books!
Lotus Cloud from Bridge of Birds gives all of her (numerous) suitors ridiculously cutesy nicknames. It's a testament to her goddess-related ability to make men become hopelessly devoted to her that Ten Ox doesn't mind being called "Boopsie" by her at all.
Every marine from Malazan Book of the Fallen is given a nickname during bootcamp. There is usually some reason for the nickname, such as Tarr being the kind of fighter to "stick" to his position in a battle or Fiddler playing one mean... fiddle. And then there's Rumjugs.
In David Carkeet's whimsical linguist mystery Double Negative, the characters' MeaningfulNames (the clumsy guy is called Woeps, the weird inquisitive guy is Aaskhugh, the soon-to-be-dead guy is called Stiph, etc.) are reinforced for the reader, though not for the slightly oblivious characters, by Aaskhugh's peculiar nicknames (his name for Woeps is "Daisy," and so on).
In Part I of Kill time or die trying, most of the older warplings aspire to this, often competing with one another to popularize their own particular nicknames for new members.
Animorphs Marco called Ax "Ax-man" (Tobias also did at times) and Rachel "Xena". He often called or referred to Jake as "Fearless Leader".
Also "Big Guy." Tobias was usually "Bird-Boy." It seems like Cassie was the only one he didn't have a nickname for, which might stem from the fact that they never really got along.
The children's book The Nickname Game had the protagonists as a pair of Nicknamers. Most of the book is spent trying to come up with a good nickname for the new girl.
Dinoverse has various humans cast back into the age of dinosaurs. Subsequently all of them come up with names for various individual prehistoric creatures. Janine is the most free with names and even continues it affectionately when back in her own time, with people who actually do have names - Candayce is Candy-Striper, Mr. London is Mr. L, Aaron is Slick.
Fat Charlie's father in Anansi Boys gives people nicknames. For instance, Fat Charlie himself isn't even really fat, but his father nicknamed him that and his father's nicknames stick. As in, it's a law of reality that they stick, because he's literally the god Anansi and the names a god gives are definitionally True. He's ruined lives by giving particularly ill-thought names.
Live Action TV
In Happy Endings Brad is this-he has a huge list of punny nicknames for his coworker Vanessa, and when Max is introducing his ex-girlfriend Angie to the gang, he specifically warns Brad against jumping the gun and giving her a nickname too soon (Brad says 'But I had Angina locked and loaded!') Also, Penny's Camp Gay friend Derrick often gives refers to her by nicknames, including 'Ty Pennington, Pennels, Penny Arcade, Pentel Pentium Processor,' and more.
Brad: Vanessa Crunch, Vanessacary Roughness, Vanessticals, the Vanessa Monologues, Vanasterbate, Its Ms. Jackson if you're Vanasty.
Lois also comes up with multiple nicknames for Clark. 'Smallville' is the most famous and prominent one.
Murdock, from The A-Team could be considered this. He frequently comes up with nicknames for his teammates (well, for B.A. and Face, at least). He usually only uses a nickname once or twice; he calls B.A. 'The Baracan One' a couple of times. His most frequent one for B.A. is mud-sucker. He's also called Faceman numerous nicknames, including, 'Visage Man', 'O Facial One', 'Man of the Countenance', and 'Faceyman' (he used all of those only once). Also, some of Murdock's remarks about Face in the fifth season episode Family Reunion have led some fans to suspect that Murdock may have been the one who came up with the nickname 'Faceman' in the first place.
Sawyer from LOST. So much so that at one point the rest of the islanders forbade him from using nicknames when he lost a bet. Juliet is noted as the only major character to not have any of them, outside of briefly being called "Blondie" in season 5's finale.
Miles is another one for nicknames. When he and Hurley first meet, Hurley complains that "the ship sent us another Sawyer", because Miles addresses him as "Tubby". Then again, Hurley gets in his fair share of nicknames throughout the series.
Dr. Cox does this on Scrubs. Elliot is "Barbie", J.D. is "Newbie" or "random feminine name", Turk is "Gandhi" or "Turtlehead"/"Turtleneck" and Kelso is "Bob/Bobbo/Beelzebob/Bobcat".
J.D. does this a lot in later seasons, too, possibly aping Cox. It becomes a plot point when he's challenged by the Almighty Janitor to name all the staff in the hospital by their real names because they're all so annoyed by the constant nicknames.
The Janitor also does this, calling Elliot "Blonde Doctor", Turk "Black Doctor", Cox "Angry Doctor", and Carla "Scary Doctor Wife".
Colonel Doctor, Snoop Dogg Intern/Resident/Attending, The Todd, Doctor Beardface, Tasty Coma Wife, Gift Shop Girl, Crazy Eyes Margo, and Cabbage. Even the Janitor is a nickname, and he sometimes goes by "Dr. Jan Itor".
In one episode, where J.D. is assigned with surgical teams, he gives them all nicknames. They all sound strangely phallic.
Kelso calls Turk "Turkleton." His real name is Christopher Turk, but even his wife just calls him Turk. Kelso may honestly believe that his name is "Turk Turkleton," or he may have been spouting nonsense because he was just that drunk.
Bernard Black of Black Books often bestows various nicknames on his employee/flatmate Manny, e.g. "Thor", "Gandalf", "Bigfoot", "Hawkwind", and "Ming the Merciless".
On Friends, Ross had trouble remembering his students' names, so he came up with nicknames. Elizabeth was "Cutie McPretty".
Similarly, Joey names the other people in the apartment building this way. Examples include "Some Kids I've Seen" and "Guy with Red Hair Who Does Not Like to Be Called Rusty".
Ross has had many short-lived nicknames over the course of the show, notably "Rossatron", "Mother Kisser", "The Divorce Force" and "Bobo the Sperm Guy".
Ross: "Hey Joe, while your over there can you get a beer for the Rossatron?"
Joey: (look of horror) "...Is that back?!?"
John Crichton, and to a lesser extent, Chiana, on Farscape did this to almost everyone. Nicknames include:
Heavy D, D (D'Argo)
Sparky, Spanky, Fluffy, Guido, Buckwheat (Rygel)
Grandma, Wrinkles (Noranti)
Scorpy, Grasshopper (Scorpius)
Harvey (Scorpius' neural clone)
S.S. Buttcrack (Moya)
Old Man (Chiana's nickname for Crichton)
Andy Bernard from The Office is a fan of doing this, such as calling Jim 'Big Tuna', simply because of his lunch choice.
Andy's even called Jim and Pam's unborn baby by Baby Tuna.
Michael Scott was also a fan of this, not so much around the office itself but he did use it for clients and such as a way of quickly remembering new people. See for instance his introduction of Darryl, and the episode where he is giving a speech in another Dunder Mifflin office branch.
Shawn Spencer on Psych seems to have no shortage of funny nicknames for Gus when they need aliases. Although,"Gus" itself is a nickname as the character's full name is Burton Guster.
He also called Lassiter 'Lassie' and Juliet 'Jules'. The only people that didn't get this are Vick and Henry.
There was a Seinfeld episode where everyone at George's office gets a nickname, by order of the boss. George eats a T-Bone steak, in a blatant attempt to get the macho nickname of T-Bone. It doesn't work, some coworker gets his coveted nickname instead, and he gets stuck with the nickname Koko (as in, Koko the monkey). He manages to get rid of it, but instead gets an even worse one instead, Gammy.
Xander makes up nicknames for nearly everyone. (Contrary to most fanfic, though, he never reuses them, which might be why we almost never hear him give Willow a nickname... he ran out of original nicknames for her years ago.)
Spike also does this. He calls Willow "Red" a few times, and Illyria "Big Blue", "The Leather Queen", "Fred Sonja", "Little Shiva", "Babe the Blue Ox", and "Blue Meanie". Most of the other cast is called by their nickname only once or twice. Also, he calls Angel "Captain Forehead" and "Ol' Broody-pants".
But if you are a girl, especially Buffy or Fred, expect to be called "Pet" or "Luv".
He calls Dawn "Little Bit" and "the Niblet" sometimes.
Faith had a habit of calling Buffy 'B', but does so less later in the series.
Gunn sometimes called Wesley 'English' in reference to his nationality.
Lorne always had food-themed nicknames for Angel.
Angel: "And stop calling me pastries!"
Somewhat like Xander above, Topher on Dollhouse usually uses real names but often makes up nicknames. Most are only used once; his most persistent one is "Man-Friend" for Boyd.
The Ned's Declassified School Survival Guide episode "Guide to Nicknames" had Cookie invent a machine that would give people nicknames based on their appearance and personality, which resulted in Loomer and his goons recruiting Cookie to give them names to insult people with. Meanwhile, Moze wants to shed her nickname and be called Jennifer.
Stargate SG-1: Jack O'Neill does this to people he doesn't like, especially the Goa'uld. The jury's still out on whether that's defiant scorn or an inability to remember their (sometimes hard-to-pronounce) names. There was one annoying human character whom he called "Sparky," and he refers to Teal'c's symbiote as "Junior."
Stargate Atlantis: John Sheppard does a similar thing with all the Wraith they meet, including Steve, Bob, Todd, and Michael. (The Wraith either don't have names or don't tell Humans their names, so Sheppard generally gives them very ordinary, human nicknames to make up for it). Lt. Ford tries to name a lot of things, but he is repeatedly shot down by the master (aforementioned John Sheppard), most notably in the debate between calling the Lantian Shuttle "Gate Ship" (It's a ship that goes through the 'Gate!) or Sheppard's version: Puddle Jumper. Sheppard wins out in the end.
Spinelli, resident Cloud Cuckoolander of General Hospital, pathologically refuses to call anyone by their given name, instead nicknaming them according to one of their perceived attributes. A short list:
Jason (Stone Cold)
Sonny (Mr. Sir)
Carly (The Valkyrie)
Jax (The Valkyrie's White Knight)
Spinelli (The Jackal)
Sam (The Goddess)
Alexis (Mother of The Goddess)
Malcolm Tucker from The Thick of It and In the Loop has an insulting nickname for everyone. He hardly ever uses the same nickname twice, but they are inevitably themed - Julius Nicholson's relate to him being bald ("Nosferatu", "Baldemort"), Ollie's relate to the fact that he looks young ("Joe 90", "Baby from Eraserhead"), and Nicola seems destined to be stuck with "Glummy Mummy".
House provides a Jerkass version of this trope. He comes up with new, insulting nicknames for everyone every time he sees them. Only one sticks: "Thirteen" for Dr. Remy Hadley. Although black Mormon "Big Love" and Cutthroat Bitch both had pretty good runs. House not calling Amber Cutthroat Bitch even makes for at least two distinct OOC Is Serious Business moments.
Jeremy Clarkson on Top Gear assigned his co-presenters (Richard "Hamster" Hammond and James "Captain Slow" May) their nicknames. They stuck, and have been affectionately taken up by the fanbase.
Hiro from Heroes does this enough that it might as well be one of his superpowers. Sylar is "Brain-Man", Daphne is "Nemesis", Matt Parkman's baby is "Baby Stop-And-Go", Nathan is "Flying Man", Claire is "Cheerleader", and Samuel is "Evil Butterfly-Man". Fans tend to accept the Engrish forms of Hiro's nicknames as their own. Isaac => Mister Isaac => Mystery Sock.
When Hiro meets a man in Africa who has the same power as Isaac, he takes to calling him "Mr. African Isaac." "Mister Africany Sock" hasn't caught on, though.
Dean Winchester from Supernatural often loves nicknaming people, calling Sam "Sammy" and (along with other characters)Castiel "Cas". Especially if he doesn't like you, he gives more satirical ones, like "Chuckles" and "Junkless" to Uriel and a few unflattering names to Zachariah. He also calls all priests "Padre"
Crowley refers to Sam as "Moose" several times.
Meg has regularly used nicknames for the other characters such as "Clarence" for Castiel and "Bullwinkle" for Sam. She also occasionally refers to Dean as "Seacrest".
Can't mention MST3K without bringing the hurricane of nicknames they gave the star of Space Mutiny.
It's worse than that. Joel/Mike and the Mads have no shortage of nicknames for each other. There's a massive list of all instances of this here, for those interested.
On an episode of Just Shoot Me!, an intern was giving cute nicknames for everyone in the office, except for Elliot. When he confronts him about it, Elliot learns that the intern had too much respect for him to give him a nickname. Once he got the intern to loosen up, however, he found that none of the nicknames he came up for him ("Clicky", "Snaps") were not to his liking.
CJ Cregg from The West Wing, whose nicknames are frequent but mostly one-offs. She does however have some recurring ones such as "Spanky" for Sam, "Tobus" for Toby, and "____ my man" for anyone, male or female. She also constantly addresses Charlie as "Chaz", "Chip", "Chuck", "Chuckles", "Chipper", "Sparky", "Gilligan", etc (the two of them have a lot of semi-adopted-siblingrivalry.)
Josh also has a little bit of this going on, like his random decision to call a high school boy named Billy "Fred" throughout an episode just for the hell of it.
On Glee, this is just another part of Sue's magnificently evil personality. Emma Pillsbury is called any woman's name but her own ("Wilma", "Edna", and "Edith", among others). Principal Figgins is "Figgy". Tina? "Asian". Mike? "Other Asian". Mercedes? "Aretha". Artie? "Wheels". Kurt? "Gay Kid", "Don Knotts", and "Ladyface".
Lampshaded when Kurt protests that last one, and Sue allows him to choose from three other possible nicknames: Gelfling, Porcelain, and Tickle Me Doe-Face (he chooses Porcelain).
Blaine is either "Other Gay" or "Young Burt Reynolds".
Subverted in Season 4, when she can't come up with an insulting nickname for Marley, because she's too nice.
JohnPope, from Falling Skies has a habit of giving people nicknames (accurate or not) that only he ever seems to use.
Rumpole of Rumpole of the Bailey gives most characters in the series nicknames, most of which only he uses. Some of these are affectionate (e.g. "Portia" for Phyllida (Trant) Erskine-Brown), some are joking ("Soapy Sam" for Sam Ballard, "Miz Liz" for Liz Probert), and some are not particularly complimentary ("Bollard" for Ballard, and the judges—"The Mad Bull" for Mr Justice Bullingham being the most notable). The most notable is his nickname for his wife, which she never hears: "She-Who-Must-Be-Obeyed".
On M*A*S*H, Frank Burns will always be "Ferret Face." And the movie is where Margaret Houlihan received the nickname "Hot Lips."
Fonzie on Happy Days had nicknames for Richie (Red), Joanie (Shortcake), and their parents (Mr. and Mrs. C).
On Punky Brewster, Punky gives herself her nickname because she hates her real name—Penelope.
Ace in Doctor Who, most famously calling the Doctor "Professor", even when asked not to. In her first appearance, she also consistantly calls Mel "Doughnut" for no apparent reason and refers to Sabalom Glitz as "Bilge Bag" (which yes, is more a term of abuse than a nickname, but the point is she never actually uses his name). And of course, her own name is Dorothy.
Cat from Red Dwarf rarely refers to his friends (and Rimmer) by their real names. Lister is "Monkey Boy", Kryten is "Novelty Condom Head", Kochanski is "Officer Bud-Babe" and Rimmer is "Goalpost Head" or, on one memorable occasion, "Trans Am Wheel Arch Nostrils."
On Criminal Minds Garcia nicknames everyone and amazingly, manages to come up with a new nickname every time. She and Morgan also, of course, have their flirty phone banter, which is only made more amusing by the ridiculous nicknames they come up with for each other. In one of the latest episodes, their phone banter leads to a sexual harassment seminar.
Damon from The Vampire Diaries gives clever little nicknames to everyone, and rarely calls anyone by their real names.
For better or worse, Nate in Big Nate has gained a reputation as the school nickname guru.
Peppermint Patty, early on—though technically she only nicknamed Charlie Brown, "Chuck". She also called Lucy by her full name, "Lucille".
Lucy: "Lucille"? "Chuck"?
Charlie Brown:(grins nervously)
Zoe of Baby Blues has nicknames for every person in her class, based on their personal habits.
The Dragon Lady from Terry and the Pirates refers to everyone as 'something one'. Pat Ryan is 'handsome one', Terry Lee is 'youthful one', etc.
Rudy the Living Dummy from FunHouse. At the start of each game, Rudy will give each player a nickname, then uses it throughout to refer to him.
Man: Oh...if it's like that, then you must call me Widget!
Woman: Well then, you must call me Pammykins!
Man: And you must call me Twimble-Twonk!
(after lengthy debate regarding the matter)
Woman: Then who's he?
Man: He's Wilkinson.
Woman #2: But you must call him Zog, King of the Pixies!
Police Chief Damon Gant from Phoenix Wright: Ace Attorney, who usually uses a variation on their surname (e.g. "Edgeworth" becomes "Worthy" "Or should I say un-Worthy", "Wright" becomes "Wrighto", the Judge, Udgey).
Also Larry, who appears to have officially dubbed Phoenix and Edgeworth "Nick" and "Edgey." He has also dubbed Franziska von Karma "Franzy".
Pearl is something of a nickname catcher, as only her mother calls her by her proper name - Phoenix calls her "Pearls" (in the Japanese version, her first name+chan) and Maya and occasionally Mia calls her "Pearly".
And then Dual Destinies brings us Simon Blackquill, who also nicknames everyone. Usually it's an insult ('Fool Bright' for Fulbright, 'Your Baldness' for the Judge) but usually nicknames the lawyers by sticking '-dono' onto the end of their surnames (eg. 'Wright-dono').
Norma Beatty from Tales of Legendia makes up nicknames for everyone she meets (and gets annoyed if anyone else uses them). Nicknames include:
G Girl (Grune)
Norma gets a nickname herself from Moses, who calls her Bubbles.
Jak and Daxter: Daxter has a nickname for everyone, whether they're friends ("tall, dark and gruesome"), rivals ("feather breath"), his girlfriend ("angel cheeks"), his biggest enemy ("metalo-maniac") or himself ("orange lightning"). The list goes on. Jinx frequently refers to Jak as "pretty boy", "Goldielocks", "blondie" or "Jakey-boy".
The main character of Suikoden Tierkreis has a habit of calling characters by other names (he consistently calls Mubal "Scholar Guy", for example), which could arguably be justified since the game has 108characters in it. Lampshaded when he meets a character that nicknames him, and they both correct each other.
The Team Fortress 2 cast call eachother by nicknames all the time (guess it helps the fact they never use their real names and call themselves by their classes) but the Scout is the biggest nicknamer of all. Here is a small compilation of such "nicknames":
Heavy Weapons Guy: "Pancakes, Fatcakes, Tons-of-fun, Fat bald bastard, Fat bald fatty fat-fat, Lardfat..."
Demoman: "Cyclops, Bomb-throwing drunk"
Sniper: "Frickin' Coward"
Spy: "Shape-shifting rat"
He also calls enemies in general "Knuckleheads", "Chucklenuts", "Dummies" and his teammeates "pallies".
The Spy only seems to acknowledge the Engineer as "Laborer".
The Engineer has a few as well: "Mumbles" for Pyro, "Sawbones" for Medic, Eyepatch for Demoman, etc.
Each character from Left 4 Dead 2 do this, mostly to the Special Infected and a little bit to each other, at the start of the first campaign, Dead Center.
They're apparently meeting each other and the Infected for the first time (a testament to just how fast the infection spread), and don't know each other's names until an elevator ride, and just call out to each other "Hey, girl!", or "Suit!" They only occasionally go back to any of the nicknames they used for the rest of the game, except for Nick calling Ellis (the redneck-ish southern guy) "Hey, overalls!" or the other characters simply calling one of the charactersCoach.
As for the Specials, they don't have any kind of "official" name, so the Survivors just call out whatever first comes to mind when they first see them, like "Exploding man!"/"Barf bag!" or "Little guy!". By the third level of the campaign, they've reached some kind of unspoken consensus on what to call them (Jockey, Boomer, Tank, etc.). Only Ellis occasionally calls a Jockey by the alternative nickname "Little guy!" from then on.
Everyone in Endless Frontier, to the point that it's rare for characters to call each other by their proper names at all.
Everyone in The World Ends with You, especially Beat. Seriously, Shiki is probably the only person who uses real names. Even the items tend to use nicknames ("Pi-face's cap")
In Dragon Age: Origins, the DLC-only character Shale never calls anyone by their names and always uses the pronoun "it" towards the Player Character (referred to as "The Grey Warden" in conversations with others). When questioned about this, Shale tells the PC that golems are always referred to as "golem" or "it", so Shale just pays it back in equal measure. Nicknames include "the Second Warden" (Alistair), "the Swamp Witch" (Morrigan), "the Elder Mage" (Wynne), "the Drunken Dwarf" (Ohgren), "the Painted Elf" (Zevran), "the Qunari" (Sten), and "the Sister" (Leliana).
Ashley Williams from the Mass Effect 1 will always refer to military personnel by their jargon nicknames, calling Shepard "Skipper" and Lieutenant Kaidan "L-T".
Kasumi Goto from Mass Effect 2 will cheerfully assign nicknames to whomever she feels like, constantly calling Shepard "Shep" and referring to the Illusive Man as "Mr. Illusive."
In Dragon Age II, Varric Tethras refers to almost all the party members by nicknames, ranging from "elf" (Fenris) to "blondie" (Anders), "choir-boy" (Sebastian), "sunshine" (Bethany), "daisy" (Merrill), and "the Rivaini" (Isabela). The only exceptions are Hawke, who's on Last Name Basis with everyone, and Aveline. Aveline calls him on her lack of a nickname in one conversation; he says he can't think of a good one for her. With all the fun he makes at her expense, he still knows not to push it too far.
In the DLC Mark of the Assassin, Hawke has a similar conversation with Varric about not having a nickname of hir own. Varric will then respond with one of three nicknames: "Killer" for an aggressive Hawke, "Chuckles" for a silly Hawke, or "Waffles" for a gentle/diplomatic Hawke. He also dubs Tallis "Shivs".
Also lampshaded in the Legacy DLC. Varric is asked why he doesn't have a nickname. He responds that it's his story.
Mass Effect 3 has James Vega (yeah, Bioware likes this trope). Man-Shep is Loco, Fem-Shep is Lola(Why?) "My best friend's sister growing up was Lola. Older sister. Hot. Tough.", Cortez is Esteban, Garrus is Scars, Tali is Sparks, Liara is Doc and Javik is Buggy.
Javik, on Joker:
The pilot insisted I let him call me "Prothy" the Prothean. I insisted he allow me to throw him out the airlock.
If the player character of Vampire: The Masquerade – Bloodlines is a Malkavian (crazy vampires who's voices in their head often give them supernatural insight) the dialoge instantly nosedives into this. They range from simple descriptions ("Nasty Dude", to an Orlock type vampire), to bad puns (a Thin-Blood who answers to E is called "the one who comes before F and G"), to Genius Bonuses (Mercurio is called the "fleetfooted god", a title of the roman god Mercury), to Foreshadowing (Jeanette and Therese are called the daughters of Janus, the two faced god; both turn out to be aspects of a split personality).
The Malkavian has one exception to this, when you call Velvet "Susan".
Rorona of Atelier Rorona does this all the time, as she's pretty ditzy (by her own admission and that of her peers) and doesn't digest long names very well. She calls her childhood friend Cordelia "Cory", the dancer Lionela "Liona" (and she also has nicknames for her two kitty puppets), and tries to get Sterkenburg the knight to answer to "Sterky", but it doesn't stick (most people call him "Sterk" anyway).
You can invoke this trope if you wish in the Pokémon games.
Dia has shades of this, though she's uninspired about it; Roland, Rashe and Rina are christened Kid, Other Kid and Other Other Kid (Girl if she's lucky) before they finish introducing themselves.
Final Fantasy IV has Namingway. The only reason to talk to Namingway is to change your character's name. Isn't that right, Spoony?
Levi the Slasher, who apparently has trouble remembering the name of anyone who isn't a fellow Material, no matter how short the name is. So she just calls them things like Original (Fate, who she was based on), Black Feather (Reinforce), and Bushido (Signum).
Lord Dearche, meanwhile, is a Royal Brat who simply couldn't be bothered to call people she doesn't care about by their name. So she just calls Kyrie "Pinkie", and calls Hayate either "Little Raven" or "Stupid Raven".
The Copy Robot from Mega Man Powered Up gives nicknames to every character except Oil Man. Here's every one:
Anghel Higure calls everyone in Hatoful Boyfriend by elaborate alternative names, including himself. They correspond to the bizarre fantasy-JRPG universe he hallucinates due to a chemical imbalance, and tend to be loaded with symbolic meanings and references that, in retrospect, are incredibly relevant to their storylines.
Wolf from the Payday series has numerous nicknames for his partner Hoxton including; Hoxtilicious, Hoxitron, El Hoxo, Hox, Hoxtinator, Hoxtonite, and Hoxifier.
Unity is an imperfect example. She always calls Sweetheart "Babes", and she decided to call the helicopter "Biscuit" despite Nick telling her he had a name.
Nick himself generally refers to people by pop-culture references, usually from video games or animation. He uses zombies for Unity, dogs for Sweetheart, and cross-dressers or otherwise genderqueer characters for Tip.
From Bittersweet Candy Bowl Daisy (Mikie, Davie, Tessie) and Chirpy (girl-kitty, boy-kitty, curly-kitty, messy-kitty, meanie kitty, boy-doggie), etc...
Yashy (Lucy/Mom) (Chirpy/Chirps) (Mike/Flea/Fleabag) (especially Daisy/Whore) (???/Blur), and Lily likes to add "-dear" to names.
Random people seem to call Mike "green eyes" and Lucy "blue eyes" in-comic. Most recent example is in chapter 61. Some readers consider it an ominous reference to a much earlier chapter.
The evil rabbit Bun-bun from Sluggy Freelance often calls people by condescending descriptive nicknames or generic names. Many are made up on the spot and only used once, such as "Alice and the wonder brain" for Oasis (whose intelligence he doesn't think much of), but some such as "Nerd-Boy" for Torg, "tube-rat" for Kiki the ferret, and "Zucchini Face" for Aylee the alien have stuck. Human women he tends to call "toots" just because he seems to have sexism as a minor hobby.
Similarly, Daniel O'Brien is this, but only towards Cracked Head Editor Jack O'Brien.
Az of Gaijin Smash has private (except on said blog) nicknames for some of his Japanese students and coworkers. Justified in one of the earlier entries in that he had hundreds of students, "so learning everyone's names is quite hard."
In his vlog reviews of Avatar: The Last Airbender , Doug Walker blames his "white American male" status for his difficulty with remembering/taking awhile to learn the characters' Asian names. Although some got very simple nicknames like "the brother" (Sokka), "the sister" (Katara), and "the warrior girl" (Suki), others got more creative ones, such as "General Malfoy Guy" (Zhao), "Rene-Odo-from-Deep-Space-Nine" (the Mechanist), and "Azula's posse" consisting of "the gymnast" and "the bored girl" (he and Rob have considered several nicknames for the latter).
Golgotha from Noob takes this trope even further than usual. She doesn't change people's names, but their Online Alias. The nickname is usually a spin, sometime a (French) pun, on the original.
Toph from Avatar: The Last Airbender . Oddly, she doesn't use nicknames nearly as often as fans seem to think. "Twinkle Toes" is really the only nickname she ever sticks with. Others such as "Snoozles", "Sheddy," "Sugar Queen", "Madame Fussy-Britches" and "Sweetness" are all one timers.
Sokka as well. "Sparky-Sparky Boom Man" didn't stick, but "Combustion Man" did. "Team Avatar" was invented by him too.
Mr. Belvertron Butlertron of Clone High calls everyone Wesley.
In both the movie and series of Disney's Hercules, Hades had a tendency to give people nicknames.
Helga G. Patakilived for this. She would rarely call anyone by their real name. Arnold suffered the most - "Football Head", "Hair Boy", "Arnoldo", "Goody Two-Shoes"... but she had a name for everybody. Other nicknames include "Geraldo" and "Tall Hair Boy" (Gerald), "Pink Boy" (Harold), "Princess" (Rhonda), and "Ms. Perfect" (Lila).
Dr. Doofenshmirtz mentioned he loved giving nicknames. He calls Perry "Mr. Duckbill Face", and Major Monogram "Monobrow" ("because he has...that thing where..."), and he calls Carl "Dr. Coconut."... ("Yeah. Sometimes, I wish I didn't know so much.")
In Teenage Mutant Ninja Turtles (2012), Michelangelo coins the name for most villains and some equipment (such as the Turtle van now being the "Shellraiser"). He even gets annoyed when people decide to create their own monikers (or another Turtle does so).
Truth in Television: This was the first of George "Dubyah" Bush's quirks to percolate into the public consciousness, back when he was but a candidate (before even his tendency to malapropism became widely mocked). He even tagged his own senior adviser Turd Blossom. This tends to be exaggerated in parodies... Somewhat.
Used in Will Ferrell's one-man show You're Welcome America, where he plays Bush as an ignorant (but not psychopathic) manchild. In an improvised bit, he asks various audience members' occupations and gives them each a corresponding nickname.
Allegedly, Bush gave president-to-be Sen. Barack Obama the nickname "Rock Bama", which is probably the coolest thing ever. PRESIDENT ROCK.
On 30 Rock, the character "Cooter Burger" was given those names by Bush. Main character Jack Donaghy picked up the nickname "The Jacker."
In W., the nicknames are a mnemonic device that young Dubya uses to help him remember all his frat brothers names during his hazing (fortunately the brothers think the nicknames are funny instead of insulting). Impressively, he gets them all correct despite being drunk, half-naked, and soaking in ice water.
Lyndon Johnson did this a lot, too (maybe it's a Texas thing) especially with people he was trying to butter up. For example, he referred to Senator Richard Russell as "Mr. Wisdom."
Harry Truman did this too. For example, referring to Estes Kefauver (D-Tenn.) as "Cow-fever".
Mexican sportscaster Enrique Bermúdez, apart from his deep voice and his unorthodox diction, is also famous for this. Some nicknames include "Duke of Catalunya" to Rafael Márquez, "Sa-sa-sa-salsita" to Carlos Salcido, "The Matador" for Luis Hernández, and "Little Pea" for Javier Hernández.
The late Peter Freyne, a local political columnist in Vermont. Two of the ones more recognizable to the rest of the country were "Ol'Bernardo" (Sen. Bernie Sanders, I-VT) and "Ho-Ho" (Former Gov. and DNC chairman Howard Dean).
First World War ace Edward 'Mick' Mannock was known for nicknaming other pilots in his squadron.
'50s rocker Eddie Cochran was known for nicknaming. He called his mother "Shrimper" in reference to her height. Musicians Bob Denton and Richard Rae were "the Brew Brothers" (they always had a beer in their hands). The road manager for Eddie's and Gene Vincent's UK tour, Hal Carter, was "Boody" for how Carter pronounced "buddy". Not sure if it was true that he actually called songwriter (and fiancee) Sharon Sheeley "Charlie Brown" or why.
The Higgs boson has gone by the nickname "The God Particle", causing some controversy due to the name. In fact, the nickname was shortened from "The Goddamned Particle" because the thing was so difficult to find.
This seems to have been a common thing among the Romans. Many Roman names are this, and many of those aren't of the nice sort. Like Plautus ("the flat-footed"), Brutus (not The Brute, but rather "the dumb"), Claudius ("the lame"), Crassus ("the fat"), and Flavius ("the blond" (Dumb Blonde?)).
The Romans remind one of nothing so much as a bunch of gangsters, with names like Horatius Flaccus ("Flabby" Horace), Tullius Cicero (Tully "the Bean"), and Claudius Pulcher ("Pretty Boy" Claude).
In fact, the entirety of ancient Roman society was based on a system of client-patron relations that bear a striking resemblance to those of the modern day Mafia. It's quite probable that the Mafia can claim to be the last survival of Imperial Rome. Just try to picture of all those ancient Emperors as thuggish godfathers, or vice versa: quite an interesting new perspective, isn't it.
It has been a tradition in virtually all college fraternities to give new initiates a nickname. Typically, the brothers who are in charge of choosing a nickname will tap into one of two sources:
Type A: an obvious trait. Someone who talks very low would be called Mumbles, and Sasquatch would be used for a large, hairy guy. If the initiate looks like a famous person or (even an obscure) character, then they will likely be named after their likeness.
Type B: an embarrassing or amusing story from their pledge period. Examples: "Splash" for someone who trips and falls into one of their college's fountains, and "Knoxville" for anyone who may try (and fail spectacularly) to copy one of the Jackass stunts on a dare.
Type C: Completely random or done for comedic irony, such as nicknaming a very mild-mannered pledge "Stone Cold" or nicknaming a pledge known for being very masculine and macho "Cupcakes".
The professional poker scene as a whole is this trope. Most famous poker player get nicknames that they are commonly known by. However they are known by their real name as well.
Baseball legend Satchel Paige did this.
In high school, you probably did this to talk about people without them knowing.
Alternately, maybe you did this as an in-joke between friends.
Queen Elizabeth I was said to have come up with nicknames for her courtiers.
Military personnel nickname every person, place, object, building, vehicle, rank, and concept. Often this is because stuff is named either unweidly (Mark-19 Automatic 40mm Grenade Launcher aka "40 mike-mike") or blandly (2W1X1 aka a "load toad" the guy who puts all the ammo in a plane). As for abstract concepts there's "The Goat", the cadet that graduates at the bottom of the class at West Point. He gets a standing ovation and wad of cash for his trouble.
And of course any Ace Pilot worth his salt (and most of the ones who aren't) will receive a Callsign from his fellow pilots. The callsign may or may not be flattering, but remember that The Complainer Is Always Wrong, and they can always come up with a worse one for you.