>>35301403Why would you? Legends, in general should keep their name unless you're going for a joke of some kind or are talking about Nebby. No one's got time for your Pookums the Registeel unless you've done so ironically.
As for normal Pokémon, playthrough teammates and competitive Pokémon are the only ones who should be nicknamed.
I don't give a nickname to every random person walking down the road, so why would I do so to a random Pokémon who is, at best, going to be banked forever, never to see the light of day until a new game comes and I put them in each extra copy of the game for 30 seconds to auto complete the National Dex?