ok so no one has yet to comment this: another problem with assuming nuclear war kills everyone is that a nuclear warhead becomes a permanent get out of jail free card.

Everyone knows about few Russian invasions, Chinese Uighur genocide or Nagorno-Karabakh war and total inaction against these observed in various international communities, especially between nuclear capable nations. Incidents of this scale were enough in the past to start a World War or at least years long regional conflicts.

While a global (thermonuclear) war not occurring is good, genocides and invasions are generally not; I fear the fear of former is causing latter never to be held accountable.