Like how you make the moveset questions, you can make good nicknames? :D
Title kinda says it all... :3
As of now, PMs official stance on this is: "Not on the current Pokebase, sorry." As can be seen here: http://pokemondb.net/pokebase/meta/29221/thread-what-some-your-favorite-pokemon-nicknames-some-pokemon It is possible it will be allowed when the forum is up, but it's currently no on nicknames.
