Kims a cockend and maybe enough of a loose camnon enoigh to actually think of firing at US targets, but more than likely it's more bravado.
Unfortunately Trumps just as big a cockend and probably would strike NK.
Below is worse case scenario not say in it is what would happen but could.
This would be an Asian war unfortuately and potentiall affect Europe.
If the US attack NK will deffinately strike US pacific targets, SK and Japan.
If NK attack first then will certainly be against SK, US and Japan.
China won't back NK, but also won't accept any Japanese military action in the area so will either be hostile to Japan or neutral.
If china do get involved, Russia won't like the Chinese on combat mode especially if it's in reference to Japan as Russian territory is between the 2 (Vladivostok comes to mind).
Any US air base in the region would be a target which could bring areas of tge pacific and Thailand into target range.
If a soveriegn US territory is attacked tgen most of Eurooe as NATO allies would be obliged to support the US.
If the chanc eof a nuclear weapon being fired in tge region tgen that would put all regiin nuclear powers on alert including possibly India.
What looks like a arguement between 2 knobhead scould easily spiral.
As said hopefully it's just a dick waving contest and both will just go back to the usual stand off.
Nobody wants war and both are full of bluster.