I don't know quite how to make this work, but how about a scenario where the extreme right in the interwar period isn't primarily nationalist, but internationalist?
Obviously they're still fascistic, racist, and chauvanistic, but maybe they put aside individual nationalisms (German, Italian, French, etc.) for what they perceive as more important - pro-Europeanism, pro-Christian, anti-Communism, anti-Plutocrat (against Britian and the US), anti-semitism, anti-gypsyism,