What's especially interesting about the relationship of the Nazis to the Protocols isn't that the Nazi elite believed in this global conspiracy and saw in it an impetus for action (which is how they made use of the text in their propaganda), but that they self-consciously sought to recreate and replicate the supposed Jewish global conspiracy in the form of Aryan racial domination. The alleged conspiracy of the "Elders of Zion" in ruling the world was exactly the sort of thing that Hitler and his ideological predecessors had in mind for the way their own people would rule the world.
This is one way of explaining the curious fact that it was anti-semitism that became the centrepiece of Nazi propaganda. As Hannah Arendt once wrote, it is "an outrage to common sense" that the relatively insignificant Jewish Question "set the whole infernal machine in motion". But to those who believed in the Protocols (i.e., had departed from the world of common sense), the Jews appeared as the only of Europe's peoples organized in the way that the Nazis claimed was the future of the racial elite of Germany - as a super-national aristocracy, tied to no particular state and yet manipulating the whole course of European life. Hence, for the Nazi claim to be realized, they had to be destroyed.
Hitler was said to know the Protocols off by heart. This fact alone indicates that he did not approve of this document for its sheer propaganda value, but as an example to be emulated. He wanted to create an elite of "chosen people" (chosen not by a covenant between God and the tribe of Israel, as in the Jewish claim, but by their racial ancestry) organized like a secret society, and hence inscrutable to the outside world - yet holding the fate of this world in its hands, because it was viewed as the true motor of History with a capital H. This is how Hitler viewed the role of the Jews in contemporary European life, even though he once remarked that it was more likely to be an unconscious defence of shared interests rather than an explicit conspiracy.
Just as in the Protocols the true motor of History was Jewish interests, embodied in an organization whose functionings could not be discerned by factual reality, Hitler aspired to create a similar organization which would treat the rest of the world like so much raw material to be manipulated for the inscrutable purposes of total global domination - with the exception that his organization actually existed, was an explicit conspiracy, and was willing to engage in acts of extreme violence at all stages of its development. It hence offered a strange attraction to individuals who were fed up with bourgeois life and wanted to become part of an organization that "did something", even if what that organization was going to do was defined no more concretely than to dominate the entire outside world.
Yet the Jewish claim to chosenness seemed to stand in the way of this claim by the Nazi elite that in fact it was the true German who was the chosen one. It hardly mattered that the Jewish bankers had long ago stopped believing in the chosenness of the Jews as such (as seen in their general contempt for poor and uneducated Jews), and had never been much interested in politics anyway. In fact, this was an important point - for had Jews really ruled the world, and had they really been the decisive influence behind the politics of European states, then it is doubtful that these states would have viewed the rise of Hitler's Germany with such equanimity.
That the rise of Germany did appear unstoppable in the 1930s, even as the persecution of German Jewry escalated, hence provided further evidence to the Nazi or his fellow-travellers that the German race was the chosen one. So rotten appeared the structure of bourgeois civilization and its alleged Jewish backers, that it appeared that any movement willing to use naked violence towards its aims - a capability the Jews, in reality, lacked - could overthrow the Jewish rulers and the civilization they allegedly supported. In peddling such a monstrously false version of events, Hitler was showing what he had learned from his reading of the Protocols - how the combination of conspiracy and complete disregard for truth had supposedly propelled the Jew into global power, and could do the same for the Nazi. The Protocols hence were not only an instrument of his own propaganda, but instrumental in shaping the way he carried out his crimes.