us secretly deploys b-1 strategic bombers..., page-21

"Looks like NK about to be nuked very soon, IMO"

I doubt that the USA or China or Russia would use nuclear weapons as a first strike, unless they were used against them first.

If NK does detonate a nuclear weapon on SK then all bets are off.

Much more likely that a series of heavy, precision air strikes and / or waves of missile strikes will be used if needed.

The USA will know the whereabouts of most of their critical infrastructure and will be able to establish air superiority very very quickly.