Nuns on the Run (1990)

Brian and Charlie (B & C) work for a gangster. When the 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. B & C 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, B & C have to avoid their boss, Triads, police and Brian's girlfriend. There's also the problem of them being men disguised as nuns in an all women institution.