Duncan, in Dragon Age: Origins, arrives in each origin seeking new recruits for the Grey Wardens, ultimately choosing The Warden.
Morrigan's mother Flemeth does this, being the only reason the Warden and Alistair survive the Battle of Ostagar.
The Warden does this twice themselves, being the one to decide who will take the vacant thrones of both Orzammar and Ferelden.
In Dragon Age II, Flemeth serves as a villainous example of this, saving Hawke from the Darkspawn in exchange for delivering a trinket for her. It's heavily implied that it was no coincidence that she stumbled upon them and she's aware of Hawke's destiny.
In Dragon Age: Inquisition, the Inquisitor is the one who determines the fate of Orlais by deciding whether or not to let Empress Celene be murdered.
In Oblivion, this is you, being sent to find Martin, who is the last remaining heir to the throne. Since you arrive at kind of a bad moment, i.e., during an attempt to assassinate Martin, you don't have time to give him much more explanation than "You're the Emperor's son, let's get out of here!" until later.
In Final Fantasy XIV, several people are granted the Echo, the blessing of the goddess Hydaelyn, in times of great strife so that they can protect the realm from certain destruction. At least, that's what everyone believes. Shadowbringers reveals that the Echo is, as its name implies, a simple echo of the power everyone had before the world was sundered, reawakened by triggering Past-Life Memories of the final days of Amaurot. Hydaelyn's words to "hear, feel, think" are not the source of the Echo — the Echo is what allows you to hear them in the first place.Endwalker further reveals that even the Warrior of Light's status as Hydaelyn's "real" chosen hero was caused by a Stable Time Loop — she chose them because they came from the future, already chosen, and told her of the quest she would put them on.
Final Fantasy Mystic Quest sees a mysterious old man name Benjamin the chosen hero of the prophecy, the only one who can defeat the Dark King. Turns out, he had no idea and was just guessing. Oh, and the ancient prophecy was started by a bored Dark King long ago as a lark.
What little we know about the G-Man in Half-Life is that he is capable of plucking people from certain doom and replacing them where they'll be more useful. He does this with Gordon at the end of Half-Life 1 and 2, and is later revealed to have done the same for Alyx and Eli Vance at Black Mesa.
Before he went to the Realm of Darkness, Mickey left Donald and Goofy a letter instructing them to find "The Key" — a Keyblade wielder. A twist is that said Key is originally supposed to be Riku, but because he turns to the dark side, the key passes to Sora.
Kingdom Hearts: Birth by Sleep reveals that Keyblade wielders can turn Muggles into one of their own. Terra willingly turns Riku, while Aqua accidentally turns Kairi when the latter touches her Keyblade. Aqua also becomes a symbolic chooser of the one later on, when she advises Sora to rescue Riku if the latter falls to darkness.
In League of Legends, Poppy assumes that this is her purpose; to find the fabled Hero of Demacia and pass the hammer she currently wields to its rightful owner. In truth, Poppy herself is The Chosen One, but she is far too much of a Humble Hero to realize it.
The goddess Hylia in The Legend of Zelda: Skyward Sword, as part of her plan to permanently destroy Demise, needed to find someone with an unbreakable spirit to help forge the Master Sword and wield the complete Triforce. No points for guessing who she picked.
Zigzagged in Hyrule Warriors. Zelda and Impa set out to become this, and Zelda seemingly has her sights set on Link, but then an attack happens. Link sets out on his own and proves to be the chosen one himself without Impa or Zelda coming to him. Then Impa sees this and gives him the hero's tunic, making her this trope after the fact.
Gwonam: It is written: "Only Link can defeat Ganon."
A unusual example occurs in Mass Effect. Nihlus was meant to be be this and joined the Normandy to assess whether Shepard was suitable for the position of first Human Spectre. However, on the first of several missions meant to decide this, Nihlus ended up with a bullet in the back of the head, courtesy of Saren. Of course, this minor setback did little to stop Shepard from eventually taking up the role of Chosen One and saving the Galaxy.
The prequel novel Mass Effect: Revelation describes Saren in this role for Anderson. Unfortunately, Saren has a deep-seeded hatred for humans (his brother was killed during the brief war between the turians and the humans), as well as an agenda of his own. He causes an explosion that kills many innocents and then blames it on Anderson, when it's time for the latter's evaluation. Naturally, this kills any chance for Anderson to become a Spectre.
In Mortal Kombat 3, Raiden designated several characters as his chosen during Shao Kahn's invasion of Earthrealm, preventing their souls from being taken by Shao Kahn's Soulnado and allowing them to mount a counterattack against the invaders. This group consisted of Liu Kang, Kung Lao, Johnny Cage (Back from the Dead after being killed by Kahn's extermination squads due to the Soulnado preventing passage into the afterlife), Sonya Blade, Jackson "Jax" Briggs, Sub-Zero (the original's younger brother), Smoke (much to his surprise), Nightwolf, Kurtis Stryker, and Kabal. Presumably, the same applies to the Forces of Light in Mortal Kombat 9, which consisted of most of the same characters (key differences being that Kung Lao had been killed off by Kahn in the climax of the MK2 arc, Sub-Zero had been captured by the Lin Kuei and turned into a cyborg instead of Smoke, and Kitana and Jade had joined the Earthrealm heroes prior to the events of 3).
In Persona 4, the Greater-Scope Villain, Izanami, was responsible for giving the Protagonist, Namatame and Adachi the ability to enter the TV World, so that she could determine what sort of world humanity wanted. Since, Adachi was the most active prolific, she believes that what they want is oblivion.
Yaldabaoth was the one who gave the Protagonist and Goro the ability access the Metaverse, allowing them to create the Phantom Thieves of Hearts and Shido's Conspiracy, and pits them against each other as part of a twisted "game" to determine whether or not he should remake the world. However, Yaldabaoth intentionally rigs the game so that he can enslave humanity himself.
Morgana, meanwhile, was created by Igor to gather "Tricksters", and guide them in his place, so that they can stop Yaldabaoth.
In Tales of Symphonia, the Chosen Ones are members of a particular bloodline who have the potential to revive the Goddess Martel, and are selected by Cruxis, the organization of angels that runs the Church of Martel, to go on a journey to "regenerate the world", aka bring life-giving mana back to it. Cruxis is actually run by the Big Bad of the game, who is looking for a suitable vessel for the trapped soul of his sister Martel, since her body was killed long ago: the Chosen Ones are thus selected for their genetic compatibility with his sister, in order to give them the best chance of being able to "revive" her by acting as host for her soul at the expense of their own.
In Vampyr (2018), the main protagonist Jonathan Reid was turned into a vampire by someone to complete an important mission: save London from the Red Queen's wrath. Turns out this wasn't the first time either, King Arthur and Sir William Marshall were also vampire heroes before Jonathan that fulfilled the same purpose. This all makes sense when it's revealed said vampire sire is pretty much Merlin.