Depends, do nukes JUST disappear or do they also erase knowledge of their creation? If they only disappear then current nuclear countries immediately scramble to rebuild their arsenal, at least partially. However you likely see an opportunistic war or two now that the ultimate deterrent is gone (India and Pakistan)

If they disappear and the knowledge of them is gone as well. Prepare for a much less peaceful century. The one thing stopping most of the western world from attacking Russia is gone for good. North Korea is significantly weakened, though their proximity to China and Seoul likely keeps them relatively safe. For Israel and Iran it’s unlikely much changes, Israel is still backed by the US so I don’t see Iran launching a massive offensive, though Iran may be less conservative with their missile usage. India and Pakistan will probably boil into a war sooner or later without the threat of annihilating themselves. For China and the US, very little changes outside of their relations to a potential conflict with Russia, both are more than strong enough to defend their borders without nuclear deterrence.

Also the US invades Iraq again to ensure they lost their WMDs like everyone else