What if after the atomic bombings of Japan and end of World War II in 1945, the United States and British Empire took the suggestion of their scientists and turned over the atomic bomb and such technology over to control by the United Nations and neutralized their arsenals?
Wow. What kind of PoD is going to bring THAT about?
Given that the US didn't even share nuclear weapons results with the Brits, who had done the preliminary work for the Abomb, were the US's biggest allies, and despite an agreement to share the results.
Why would the US suddenly hand over all the weapons to a body they didn't control?
Seems remarkably improbable to me.
So, if you've got a whomping big PoD that causes that change, there's going to be LOTS of other changes, too. And what those changes are, and how the situation evolves will be heavily dependent on said PoD.
So, the question as asked is unanswerable, because there isn't enough info.