Any successful revolutionary program begins by applying revolutionary theory to the present material conditions. Revolutionary practice which has proven successful in one era, in one region, under specific material conditions cannot simply be transplanted to another era and another region under substantially different material conditions. During the October Revolution, nationalism was a disastrous position married to the crumbling regime and the pointless meatgrinder of World War One. During the Chinese Civil War, expelling Imperial Japan proved to be a higher priority than continuing to fight the KMT. In Vietnam, nationalism took the form of fighting for sovereignty against colonial occupation. Nationalism in the US, on the other hand, takes the form of chauvinism and pride in dominating the world.

There is a lot of context to take in. There is a substantial difference in character between nationalist movements in colonized nations and nationalist movements in imperialist nations. A nationalist movement in a colonized nation could potentially split off sections of the petite bourgeoisie from the comprador bourgeoisie, moving the situation in a direction which is more favorable for social revolution. Of course, you can also have a situation where all the nationalists develop in exile as a deeply counter-revolutionary undertaking.