Nazi Germany certainly had the capability with centrifuges developed during WW2 to enrich Uranium and at a rate much faster than Oak Ridge’s K-25 gaseous diffusion plant. Germany had at least 40 Hellage Mark IIIb centrifuges in operation from April 1944 and these enriched U235 at a rate 30 times faster than the American facility. Nazi scientists knew the mean free path neutron replication of U235 from a paper written by Fritz Houtermanns in October 1941. There were no technological barriers to the German bomb.
Nor was there a lack of delivery systems. The Heinkel He-277 entered production at Schwechat Vienna in August 1943 and by April 1944 there were four He-177 A-6 prototype airframes converted to He-277 standard. These aircraft could carry an 8 tonne bomb load to 49,500ft over England.
What prevented Germany deploying nuclear weapons was a threat made by Churchill & conveyed to Hitler by Romania’s Marshal Antonescu that the RAF would retaliate any nuclear strike with Anthrax.