They do have at least one development studio there, Nintendo Software Technology:

https://en.wikipedia.org/wiki/Nintendo_Software_Technology

They also make quite a few more changes than expected when localising games. Or at least they did in the olden days, where the American versions of games sometimes had different/extra features compared to the Japanese originals.

I think some of the localisation team are also regular voice actors for the games, on a worldwide basis.

> They do have at least one development studio there, Nintendo Software Technology.

Oh, interesting! The list of games isn't particularly impressive though, a lot of ports and remakes. Compare that to also-US-based Retro Studios, which isn't considered under Nintendo of America from what I understand.