I sometimes name my pokemon, but other times I name them after characters from other video games. Heres an example: I named my Umberon Anima (a summon from the Final Fantasy series). I also name my fire type Mario.
I rarely nickname my Pokemon because I simply forget to nickname them. However, I decided to nickname my main team in Emerald after mathematicians and scientists (and even nicknamed a Wurmple "Edison" because my opinion of him is not that great).