The Being (1981)

Two scenes of topless female nudity.

An woman is sitting on a bed fully nude in a movie showing on the screen at a drive-in. But we only see her breasts and side. She is then attacked by a monster and thrashes about. She gets tangled in the sheets as she rolls around and falls off the bed so most of her body is covered except for brief glimpses of a breast. In the drive-in audience, a teen couple make out in a car. They start undressing, but no nudity seen at this point. Since it's a horror movie, you know they are going to be attacked, and she briefly shows one bare breast.

Several scenes of bloody kills and mutilations, and one beheading.

A few uses of "fuck", "shit", and other minor profanities.