There have been plenty of threads discussing the likely ramifications of 1962's Cuban Missile Crisis spiraling into a full nuclear war between the United States and the Soviet Union. While I'm not an expert in the technical matters relevant to such a discussion, I can glean from such threads that the most likely outcome seems to be one where...
1) The United States is mostly or completely unscathed by the conflict, given the massive advantages that they enjoyed over the Soviet Union at the time.
2) Western European countries aligned with the United States (the United Kingdom, France, West Germany, etc) take moderate to severe amounts of damage, but ultimately survive as functional states.
3) The Soviet Union and most of the rest of the Warsaw Pact suffer horrendous levels of military and civilian casualties and are effectively ended as coherent entities.
While such an event would have myriad political, economic, and social effects for the entire globe, I do note that the United States would be left in an entirely hegemonic position on the world stage, one far more profound than what they enjoyed in the immediate aftermath of the Second World War, and will likely fully exploit that position.
With that in mind, after a few years of postwar chaos in much of Centrla and Eastern Europe, what would the continent's borders look like by 1970 in this timeline? Here are some thoughts...
- Germany: Again assuming that West Germany survives the war as a functional state, not only is reunification with East Germany pushed up by a few decades, but I have to believe that this German state would push for a revision of the Oder-Neisse line and a return of the lands that had constituted their 1937 eastern borders (i.e. Silesia, Pomerania, East Prussia, etc) from Poland and the former Soviet Union. The West German government had yet to recognize the Oder-Neisse line as valid, and expellees from the aforementioned areas still formed an influential lobby in German politics. Furthermore, Poland itself would likely be badly damaged by such a war. I could see the United States acquiescing and granting these borders to Germany, and if there are enough Poles left to seriously complain, Washington might compensate them with a return of some or all of the pre-1939 eastern territories (i.e. Kresy) that they lost to the Soviet Union.
- Poland/the Baltics: Poland and the former Soviet republics in the Baltics will be badly damaged by such a war - so much so that there might not be enough people in some of those areas to build a coherent state around afterwards. In such a scenario, might the United States form some sort of federation of Poland, the Baltics, perhaps Belarus (essentially a revived Polish-Lithuanian Commonwealth)?
- The USSR: Much of European Russia will likely be reduced to a post-apocalyptic wasteland in such a scenario, but on paper, how might the United States try to organize this territory (beyond giving some land to other states - as aforementioned, Poland could get some land, and perhaps Finland would as well)? It is probably a given that Ukraine, the Caucasus republics, and Central Asia will get independence, but might other peoples in less damaged parts of the former get their own states as well, de jure or de facto? For instance, the Chechens, the Kalmyks, etc.
Anything else I might have missed?