Nations can be created over time, even across ethnic, linguistic and religious borders. Thousand years ago, while there was a budding French and German nationality, nobody could have imagined a Swiss or Belgian identity. Even in 1500 a Dutch nationhood would have been hard to define, since most parts of the Eastern Netherlands rather were Low German than sopecifically not-German. An Austrian nation certainly exists now, but before 1866 "Austrian" was rather comparable to "Saxon". "Bavarian", "Hessian" - a certain subset of Germans.
So - what places and regions had enough local identity that could have developed into a true nationalism until only a few crackpots advocate an union with the "motherland"? Some ideas are:
~"Prussians": If the Duchy of Prussia stays apart from German states further west, the people might feel as a separate Baltic nation, emphasizing their unique chivalrous past or even their Prutenic inheritance.
~"Sicilians": Only the insulars, different from North as well as South Italians, again, emphasizing their unique position and history.
~ "Gauts": That would need an early PoD, but the area of the two Götalands, Smaaland and Värmland might have developed in a country of its own - a permanent buffer between Sweden and Danish Scania.
What are your candidates for AH nationhood?