I got it, Trailboss.No problem here.
That's why I said the line was close but not over and that "I like it so it must be in good taste." As a matter of fact, part of the comedic tension in the setup was to create the expectation of some vulgar, cheap, hackneyed punchline about nuns. The punchline itself relied on the surprise and release of that tension.
As I said, I liked it.