I used my real name for my character's name (because it's a luxury now, as I have an 8 letter name and prior to XY I was unable to use it). However, my character's nickname was "daddy" for the memes.
Well in X, I played as the girl character and nicknamed the player PokéMay, from the combination of Pokémon and the name of my player May because I liked Hoenn so much and I totally wasn't a creative person back then.
In Y, I played as the boy and I think I named my character 'Big X', but I can't really remember. Pretty sure it's because I named my character Xavier, after the name of the male protagonist in the X and Y prerelease trailers.
Ill either name my protagonists, Lrdgold, or my irl nickname, or whatever their canon name is. Always name my rival whatever their canon name is as well.
During my first play-through of X version, I picked Kitsune as my nickname, because I was really interested in youkai and Japanese folklore back then. In Y version, my nickname was my actual real-life name. I just didn't feel like making a more creative nickname in that game.
Raptor, because Tyranitar is so epic, so empowering, so immortal, and eternally triumphant, that tickling your tummy for more ice cream cones, as he evolved from Red's Mt. Silver Cave to the peak, he's kind of like Saruman besting Gandalf, since Count Dooku is Darth Tyranus, or Tyranitar.
I've always used my real name for when I play as the female characters so I just used my actual nickname too.
It's only three letters long and it looks a little odd like it got cut off in the text bubbles whenever one of the characters use the nickname...