I'm going to disagree with wormyguy and say that cold fusion, caused by hydrogen somehow turning into helium in the presence of Palladium is a crackpot claim.
Can Nazi Germany get swindled into a crackpot claim? Hell yes.
Of course, Cold Fusion doesn't exist except as either a myth or an expensive sinkhole. At least on a factual basis. But Germany didn't always operation on facts. It would look something like this:
Heisenberg: WOW! I've developed COLD FUSION!
Nazis: Awesome; lets stop building so many tanks and planes and try to weaponize it!!!
Heisenberg: Awesome! Thanks for the $$$.
[Four Years Later]
Nazis: The Soviets are knocking on Berlin, do you have it yet???
Heisenberg: Not quite yet, I just need to try it a little differently.