The idiom "go nuclear" means to become extremely angry or to use extreme measures to solve a problem. It comes from the idea of using nuclear weapons, which are the most powerful and destructive weapons known to man.
You would use this idiom when someone is very angry and is about to do something drastic or extreme. For example, if a boss is very upset with an employee and threatens to fire them immediately, you could say "Wow, the boss really went nuclear on that employee."
Another example could be when a sports team is losing badly and the coach decides to make drastic changes to the lineup or strategy. You could say "The coach really went nuclear with those changes."
Overall, "go nuclear" is a way to describe a situation where someone is using extreme measures or is extremely angry.
• If he doesn't stop teasing me, I'm going to go nuclear on him!
• I was so angry that I almost went nuclear.
• The coach went nuclear on the team after their lackluster performance in the championship game.
• The government warned that if the neighboring country attacks, they will go nuclear and retaliate with full force.
• The situation was getting out of hand, so the company decided to go nuclear and fire all the employees involved.
• The CEO went nuclear when he found out that the company's confidential information had been leaked to the media.