>>17062752>>17062798I was originally of the stance that nicknaming Pokémon was stupid since they already had awesome names, but around Emerald was when I started giving nicknames (though I couldn't think of one better than Blaziken for my Blaziken, so I just formatted it). Done it ever since for travelling companions.
Exception to the rule is Legendary mons, which I feel weird naming. Lore wise you have no real reason to define them as separate since there's only supposed to be one, so I just leave them with whatever name they have.