DanG's referring to this one that came out in 2000.


Plot: The abbess (Moyna Cope) of a convent invites the leader of a group of monks (Simon Hill) to visit her and offer needed advice. A wave of sexual temptation has begun to flood the convent, with the Mother Superior (Sally Tremaine) having bizarre sexual fantasies about Mary Magdalene (Kristina Bill), and many of the other nuns suddenly attracted to each other (i.e., lesbian nuns run amuck). However, the presence of a man only fuels the fires of a potentially explosive situation.


This is from an Italian porn called Il Mistero del Convento., came out in 1993. Deborah Wells was in it.
Drop a post at dvdmaniacs.com...they'll probably know more.

FWIW, Swedish model Anita Ekberg was in a nunsploitation film called "Killer Nun" from the early 80s, but probably too much jungle for you.