not really a simulation but the movie “threads” gives what seems to be a very crude and realistic potential scenario viewed from the population standpoint.
I still have nightmares about threads - the interesting thing about threads is that it shows the expect tactical flow of nuclear war at the time where they expected a big city, but not london to be the first target. It was always presumed Birmingham, UK would be hit first
When the wind blows by Raymond Briggs is scary too as its so matter of fact
Also the US movie "The Day After", and the Soviet movie "Letters from a dead man" come to mind. We discussed those in school in East Germany in the 80's. TL;DR: not much point in "simulating" a nuclear war, it will be the end anyway.
When the wind blows by Raymond Briggs is scary too as its so matter of fact