Nuns on the Run (1990)

Brian and Charlie work for a gangster. When their boss learns they want to "leave", he sets them up to be killed, after they help rob the local Triads of their drug dealing profits. They decide to steal the money for themselves, but when their escape doesn't go to plan, they have to seek refuge in a nuns' teacher training school.

Disguised as nuns, they have to avoid their boss, Triads, the police, and Brian's girlfriend. There's also the problem of them being men disguised as nuns in an all women institution.