This is foolishness to the tenth power.
Suppose the worst, and NK could launch and detonate a (small) nuclear device somewhere on US territory?
If they did that, what would be the result?
If you said the end of North Korea, the death of its leaders, and an object lesson to the rest of the world - you would be correct.
Our losses would be minimal. Theirs would be terminal. Even to consider it is absurd.
Nukem already, lets move on. Enough is enough!