Is there nudity in any of the Mobile Suit Gundam series?
For the portion you're concerned with
IMDB states the following-

Some characters (including children) do appear fully naked in bath scenes. Breasts are visible on female characters, and penises are visible on two child characters in one bath scene. There is a scene where one male child character rubs the chest of a female child character, though this is more comedic than sensual.
There is implied to be a romantic interest between many characters on the show, but nothing sexual is even shown (or for that matter, hardly even implied.)

List of Bathing Scenes-
http://animebathscenewiki.com/index.php?title=Mobile_Suit_Gundam
For additional info you may refer to this link-
https://m.imdb.com/title/tt0159172/parentalguide?ref_=m_ttpg