First of all, the origins of the term Aryan refer to a superior or "highborne" in most Indonesiac (lol) languages. So basically it's a brown guy with dark hair and dark eyes. Hitler simply adapted the term with the meaning "Superior" which was dumb. So, Aryan = superior, not a blond hair/blue eyed person, unless you're looking at it from the Schutzstaffel perspective. I find it very interesting how many people are uneducated about such things as what a Nazi is and what the word Aryan means.
Second, Hitler would've used nuclear weapons because the holdout in the US would take too long (look what happened to his patience with fucking Britain if you don't believe me, and if they do indeed win the war, there would be no fault in Operation Barbarossa meaning he wouldn't have any reason not to) and ultimately doom himself, I suppose.