Nuns on the Run (1990)

Set up by their boss to be knocked off following a final heist, soon-to-retire crooks Brian Hope and Charlie McManus get wind of their impending demise and run off with the spoils of their crime. Fleeing their boss, the drug dealers they robbed, the police, and Brian's angry girlfriend, the duo take refuge in a training convent for nuns. In disguise, they convince Sister Superior that they're nuns, a charade they're forced to maintain as their enemies arrive.