Sue Prentiss, R.N. (1975)
Not having actually viewed this porn film, we at sewergator.com can't comment on any hot and horny dripping wet gator-on-gator action it might contain. We strongly suspect its sex scenes are confined to humans, but we're pleased to learn it at least makes mention of the sewergator legend. Apparently, a team of scuba divers has been engaged in a gator-hunting expedition in the sewers of New York City, and the hunters unwind from their task by engaging in sex with a team of hot nurses. For further details, such as they are, see the description below from the Something Weird video catalog.
(Thanks to Sewerfriend Art Scott for this item.)