Both games do contain nudity, even in their censored versions. Both have a shower scene, while Liberation Day also has a sex scene that isn't quite blackened out all the way. In addition, Liberation Day has a scene where a character has an out-of-body experience, with her mind depicted through relatively clean "Barbie doll" nudity; this is shown in one of the screenshots on the store page.

While I don't really mind the latter, the presence of nudity even in the censored versions of the games is something that's irked me from the start. I adore the series, but I'd prefer the games to be a bit cleaner. To that end, I myself have actually released a basic mod that censors the shower scene in Mask of Arcadius, leaving that game with no nudity whatsoever (save for a very, very minor case that's completely tasteful, largely obscured, and not at all sexualized). You can find it on the official Love in Space forums (thread link below), though I don't recommend watching the embedded video; it has spoilers and is just a series of gags for series fans.

http://loveinspace.freeforums.net/thread/516/sorzos-miscellaneous-tweaks

Unfortunately, I don't have a similar mod out for Liberation Day at the moment. Said game stores its files differently, and I don't know how to make edits to them. It's something I plan on figuring out eventually, though!

Bear in mind that even without nudity, the Sunrider games aren't exactly family-friendly. There's occasional strong language, a fair amount of blood in a few scenes, and one character who's incredibly perverted, leading to no end of innuendo and suggestive moments, though it's all played for laughs.

EDIT: I've just posted a censor patch for Liberation Day in the same thread linked above. You should now be able to play through both games in the main series without encountering any real cases of nudity.