Here's Oola, the green Twilek's wardrobe slip in Jedi!

So yes, there are nipples in Return of the Jedi. 

Green ones actually.

It's a blink and you'll miss it moment but nipples on green boobs can definitely be seen in a Star War movie:

Green space nipples.

Given that legend has it Carrie Fisher had to tape down her breasts whilst filming A New Hope (as they kept bouncing around which distracted from 'the look' Lucas was going for) it's pretty amusing for some cleavage action to occur in Jedi.

It wasn't until Rian Johnson put the pedal to the metal in The Last Jedi, that we saw some space unders actually miked though...

You can watch the green topless titty explosion video right here.