Goebbels never doubted that he was a socialist. He understood Nazism to be a better and more plausible form of socialism than that propagated by Lenin. Instead of spreading itself across different nations, it would operate within the unit of the Volk.
It is now clear beyond all reasonable doubt that Hitler and his associates believed they were socialists, and that others, including democratic socialists, thought so too.
The clue is in the name. Subsequent generations of Leftists have tried to explain away the awkward nomenclature of the National Socialist German Workers' Party as either a cynical PR stunt or an embarrassing coincidence. In fact, the name meant what it said.
Hitler told Hermann Rauschning, a Prussian who briefly worked for the Nazis before rejecting them and fleeing the country, that he had admired much of the thinking of the revolutionaries he had known as a young man; but he felt that they had been talkers, not doers. "I have put into practice what these peddlers and pen pushers have timidly begun," he boasted, adding that "the whole of National Socialism" was "based on Marx".
Marx's error, Hitler believed, had been to foster class war instead of national unity