Before the National Socialist German Workers Party, there was the German National People's Party (DNVP). Preceding the rise of the Nazis, the Party was the major conservative and nationalist party in Weimar Germany. Presenting itself as a alliance of nationalists, reactionary monarchists, völkisch, and antisemitic elements, the Party was pretty much the predecessor of the Nazis-it railed against the Treaty of Versailles and viewed the signatories as traitors and campaigned to repeal the Treaty and re-acquire all lost territories and colonies. The only major difference was that the Party was also pro-monarchist and vowed to re-establish the German monarchy.
So, in a reality where the German Workers Party never transformed into the NSDAP, could the DNVP have seized power and what would be the results of a restored German monarchy under the DNVP?