Ninten and Sony are names in the game, and they're set as the player's name if you manage to skip the name input process, which is possible to do with a GameShark code that enables a few debugging features, one of which skips the introduction cutscene.
If memory serves, those names are only in the non-Japanese versions of the game though, it was added during the game localization process, most likely as an inside joke or a way to get back at them for dropping Nintendo when they were working together on the SNES CD just a few years prior.