During the Vietnam War, President Nixon floated the idea to Henry Kissinger that he (Nixon) make remarks about nukes plus act mentally unbalanced as a way of putting the fear of God into our heathen foes. IIRC, HK nixed the idea. Of course, he’s probably the source of the story.
During the Korean War, McArthur most definitely rattled the nuclear saber, and it was part of why he was fired.
Kissenger was pure CIA beginning with his days as a young Army Intelligence translator working with Dulles to recruit German scientists to move to the USA after WWII.