The world ending arsenals of the 70s/80s. Think P&S or able archer goes hot.
In which case I think both sides would be way too devastated to even think about rebuilding, and might barely have enough people left to make the cities more than shadows of what they once were. But, say, places like New Delhi, Buenos Aires, or Cape Town, which might get hit by a nuke, but not levelled, might take a couple decades to rebuild (also including time lost due to economic dislocation and political instability).
As mentioned above, places that make sense for cities, river deltas, good harbours, etc. would probably have some settlement, while places like Washington, Atlanta, Indianapolis, etc aka human/technological conceits, would be abandoned.