Imperator Tyranus was nicknamed Imperator Trollanus after a series of snobby, condescending and downright trollish attitudes both on the IRC channel and on the semi-canon universal discussion board.
The Junction Mind - expies to the Combine Advisors - were nicknamed Watermelons after their visual appearence of round, dark green creatures made using Spore's engine bore a strong resemblence to the namesake fruit.
'Radeons were nicknamed Holyrats due to their Church Militant culture and for bearing a strong resemblence to anthropomorphic rodents.
Vyro'Narza were affectionately called Piggies or Pigmen because their models in Spore used a pig's mouth piece. This goes for both in and out of universe.
Xhodocto were forever cursed with the nickname XHODDIES. The very mention of the name has been known to send the creator into a flying rage.
Zí-Jittorám were called Plant Doods because their biology was strongly linked to plants. However with skin as hard as adamantium, enough muscle to throw tanks in a caber-toss and acidic spit strong enough to put Xenomorph blood to shame, they're perhaps one of the toughest species of plant creature in the wiki if not ever in the history of all fiction.
Skhánaróton -01, having a difficult-to-pronounce firstname was nicknamed Plant Dood because he is a member of the Zí-Jittorám race. Another recurring nickname is Skhánaman.
Due to their holier-than-thou Light Is Not Good nature, the now-destroyed Obvia'Atra gained the nickname of Obvia'Arsehole because any time they dealt with mortals they were extremely condescending about it.
The Kraw Galaxy, a sattelite of the Andromeda Galaxy, is known as the Hillbilly Galaxy after the dumb-as-soup reputation of its denizens who frequently had little clue what was going on outside their little galaxy. Some going as far as to consider the science of the more advanced empires (such as the knowledge of essence) as nothing short of reality-defying magic. Being the Straw Atheists that they were they often threw fits.
The secretive nature of Mentracu, the Spymaster for the Draconid Imperium has transcended the bounds of the fictional universe has earned hi mthe nickname of 'Witchcraft Guy. "Originally" revealed to be the sender of a black screen. A simple change in the brightness and contrast of the screen revealed something form nothing, leading the discoverer to cry out "Witchcraft!" on the IRC. It was then discovered that Mentracus had a fully-developed page that went completely unnoticed until it was pulled out of the depths of the Sporewiki's page archive.
Flip Flop of God: No one is quite sure if the Universal Discussion Board is canon or not. As far as most users are concerned, it's canon, but only when necessary.