I nickname my pokes more often than I used to, but still not that much. One of my casual teams for fair game against non-competitive battlers is themed on musical terms.
Metagross - Overture
Machamp - Adagio
Alakazam - Allegro (Allegra D?)
Salamence - Forte
Garchomp (OH NOEZ AN UBER?) - Intermezzo
Gyarados - Symphony
Also have an ubers team themed around Prince of Persia (360).
Kyogre - Alchemist
Palkia - Concubine
Latios - TheWarrior
Mewtwo - TheHunter
Darkrai - Ahriman
Arceus - Ormazd
Uncreative and possibly lame, yes, but I'm terrible at nicknames. So... yeah.