I always nickname my Pokemon. I usually give them humane names and sometimes use translated words based on nature, etc for nicknaming. When I name a genderless Pokemon, they'll be named after the surname,universal name, etc.
I used to never nickname my Pokemon, but I've taken to naming them lately. I recently got Pokemon Pearl and EVERY Pokemon has a foreign name except an in-game traded Abra and a random Zubat I forgot to name