I can't say that any of my Pokemon nicknames are brilliant, but they are original!
Charmeleon - Tyr, which is the name of some Norse god...
Pikachu - Laurel, the name of a church group...and it just stuck! ^^;
Rattata - Bryan, which is normally the name of my Bagon...o_o
Kadabra - Kitsune, because Abra looks like some sort of fox!
Pidgeotto - Tara, just because. They seem to pick their own names...o_0
Mankey - I named him Bruno and couldn't figure out why until I remember the Elite Four...Whoops! ^^;
Then I have a Meowth named Celeste, another Pidgey named Hawkes, and my Skarmory Triplets on Ruby: Angelus, Kira, and...darn, the last one started with a 'T'...Eh, I'll remember it eventually!