Patriot is good.
Top Gun could lead to an interesting discussion.
Gettysburg and Glory are good examples of Nationalism explored in the context of Civil War. Glory also looks at racism in wartime.
A more recent movie, The Great Raid, was a good example of Nationlism, good and bad, in film. It also looks at how Nationalism and racism is used to justify atrocities and war crimes. Pretty deep subject matter if you want to go down that path.