Depends how early or late the victory would have been. Kind of like every discussion on the Republican victory. I would say an early victory before the suppression of the more revolutionary elements of the Spanish coalition would have been a pretty big toss up, depends on who has influence, what the government in France is, and a whole bunch of other stuff. A later Spanish Republic dominated by the liberals and communists was likely to forced into the war in 1941 after toeing the stalinist line about not confronting Germany.