Their is no might, Nazi Germany would definatly still be around today and no doubt control a huge part of world.
It is highly unlikely that Nazi Germany would have surviced Hitlers death, be it by his own hand, someone elses or natural causes. Trying to control a huge part of the world by oppression is unrealistic and the wealth of opposition was plain at the time.
The USSR would not have tolerated a Facist Regime for very long, neither would Japan who had no love of Nazi Germany anyway. The US/British alliance was a lot stronger than you seem to think, in fact if not for the Americans Churchill was all for continuing into the USSR to subdue them before they got any stronger.