Secret underground tunnel to Nazi nuclear test site found in Upper Austria ?

[Bacon King]

Fun fact: Allied intelligence had spies amongst the Swiss academia who would regularly attend lectures that Heisenberg gave on nuclear physics. There were standing orders to kill him if his understanding of the subject matter was ever determined to be sufficiently accurate and advanced to design a functional nuclear weapon. Fortunately for Heisenberg his ideas weren't entirely on the money

[Bacon King]

Possibly the Nazis might have progressed to the point of being able to build a crude reactor, but even had they developed bombs equivalent to Fat Man or Little Boy, they didn't have a delivery system able to carry such heavy bombs.  The best they could have done would have been to use it to as basically an atomic mine, hiding a bomb that would be blown up once the enemy had taken the area.  Maybe detonate it in Berlin itself as part of the Nero Decree.

You couldn't stick one on a V2?

A nuke would have been too heavy of a payload for a V2 to carry and even if that wasn't a problem I think it would be really difficult to design a bomb that wouldn't blow up prematurely due to the V2's supersonic speeds