He wins Barbarossa, peace with the UK and let the cold war begin.....PS: The Krauts were a decade away from a ‘bomb’ in ‘42.
A win of Barbarossa would have resulted in a redoubled hot war on the Axis’ western flank since that meant the eastern front was secured. Neither Hitler nor Churchill (already at war for two years prior) would have sued for peace in such an eventuality. Wins emboldened Hitler rather than made him settle for any sort of “cold war” situation.
The Allies were in fact convinced that Nazi Germany could have achieved atomic breakout before the war actually ended, particularly due to the fact that it was in 1938 that German scientists discovered how to induce nuclear fission (hence missions like Operation Big). Should Hitler have secured the whole continent, he would have had the time to produce atomic weapons far more rapidly, and he would have used them.