The Thompson submachine gun, more commonly referred to as "Tommy gun", is an American submachine gun, invented by John T. Thompson in 1919. The weapon became infamous during the Prohibition era. It was a common sight in the media of the time, being used by both law enforcement officers and criminals.
In "Nation's Pride", a few American soldiers are seen carrying the M1921 version. M1928A1s, M1s, or M1A1s would have been more time-appropriate, but it's very likely that since "Nation's Pride" is a German-made film during WW2, it would be easier for the in-universe armorers of it to acquire older M1921 Thompsons.