This is actually a great plot for a supervillain in a movie. Simultaneously detonate all nuclear weapons on Earth, albeit at 3% of it's power. That would seriously fuck us up.
Most nukes are underground, so most of the fallout would be contained. And the result would be a world not fearing anymore for accidental or intentionally nuclear anhilation.
So most would consider that supervillain a super hero.
It would work if the villain sells conventional weapons - we've been itching for a conventional world war for a while now, and nukes are the only reason we've not been able to.
Peace?
You mean there was no world war, but there were and are plenty of wars going on all the time. Also it is quite a risky bet, to assume all the actors will remain rational.
The only two actors capable of inflicting gigadeath are still the US and Russia. Both of them are ultimately run by oligarchs who want to remain alive, and have a population to lord over.
The actors who are genuinely irrational don't really have the number of nukes to do more than cause ~megadeath. This sort of thing would only happen once and then the actors would cease to exist.
That does actually sound like a good plot - do something ostensibly "villainous" by stripping countries of their beloved nukes, but be hailed a hero for it. As in, it would be an actually smart way for a villain to rehabilitate their image. And then, you know, 10 years down the line they could build their own super-weapon, perhaps. This is why I'm not a screenwriter.
Most nukes are underground, so most of the fallout would be contained. And the result would be a world not fearing anymore for accidental or intentionally nuclear anhilation.
So most would consider that supervillain a super hero.