Assuming this is a Cold War, somewhat analogous to OTL. All the stuff about "Jewish Science" aside, once the Allies demonstrate that an atom bomb small enough to fit on a four engine bomber is possible, Germany can build their own and will. Even if you have a period where the USA has a major lead in nukes, like OTL, once the "bad guys" develop the ability to vaporize even a few US cities the calculus changes. The ensuing Cold War then lasts until the Nazi regime collapses internally, or the Nazi leaders go all Klingon "it is a good day to die" either believing they have a military advantage or as a desperation move if they see collapse staring them in the face. The major difference between the USSR and Nazi Germany is that while the USSR had an ideology that was universalist in nature ("workers of the world unite") and exportable, Nazi ideology holds no attraction for most of the rest of the world. Don't forget the folks in Eastern Europe who cooperated with the Nazis, once Generalplan Ost was put in to effect, were just more Untermenschen to be disposed of or enslaved, so if you aren't Aryan cooperating with the Nazis for temporary gain is not a good move.
There are plenty of competent technocrats like Speer in Germany, the question is over the long run will they be given enough authority over economic matters to keep the system going. Per se Nazi ideology is less inherently economically nuts than communist ideology. Are the ideologues and fighting factions going to keep messing up the economy after "victory", maybe yes and maybe no. Once you get to "MAD", the situation is stable unless one side or the other collapses internally, a spark is igniting accidentally, or one side goes Klingon for one reason or another. While a Reich with a shambolic economy is certainly very possible, it is not inevitable. Had the USSR not had this problem, we'd have the Cold War going on today. The same applies, sadly, to the Nazis.