I think no-one. North Korea is probably bluffing that they will actually use nuclear weapons to gain leverage in negotiations. They get global attention, and are less likely to be overthrown in the process.
I doubt the North Koreans will initiate any attacks on the USA, and there is no way that Trump will attack first, Even though he wants the Kin Jong Un out he will not start this and kill North Korean civilians will be casualties of the war, He seems to care more about them than their own President.