The full tweet referenced by the article:
If Iran does anything that stops the flow of Oil within the Strait of Hormuz, they will be hit by the United States of America TWENTY TIMES HARDER than they have been hit thus far. Additionally, we will take out easily destroyable targets that will make it virtually impossible for Iran to ever be built back, as a Nation, again — Death, Fire, and Fury will reign upon them — But I hope, and pray, that it does not happen! This is a gift from the United States of America to China, and all of those Nations that heavily use the Hormuz Strait. Hopefully, it is a gesture that will be greatly appreciated. Thank you for your attention to this matter! President DONALD J. TRUMP
So is the military going to refuse “illegal orders” when he orders them to fire nukes?
Also if he does use nukes against Iran then Russia would definitely start using them against Ukraine. It will become a free for all.