There is no justification for using nukes. Even just keeping them on standby led to tons of accidents that almost resulted in detonations or nuclear war.

I know that's not a very nuanced take and there are reasons countries pursue nuclear arms, or maintain nuclear stockpiles, and a lot of that has to do with the USA having a giant arsenal of them. They're bad though, folks. Ideally nobody should have or use these wretched machines. The bombings of Hiroshima and Nagasaki are crimes against humanity.