Nuke is just there for preventative measure. Nobody in their right mind will threaten anyone with "nukes". Of course Putin is crazy so there's that but that's desperate.
Only fascists talking about using nukes.
Unfortunately the precedent of using nukes on civilian cities Hiroshima and Nagasaki is a fact. There was no military need for it as the Japanese army was not there and remained intact and had to be fought by the Soviets. US tried to put a scare on Stalin and failed miserably.
There is a reason why ninethirty said that he is not afraid of Russia using nukes(attaboy). And as a matter of fact Putin never mentioned nukes, it was actually Biden who mentioned nuclear Armageddon which implies that he is hell bent on refusing to retreat like Kennedy did in Cuban missile crisis by removing missiles from Turkey. There is also an indirect implication that US citizens who don't want to die and go to Valhalla are obviously pro-Kremlin.
Elon Musk obviously understands how serious the situation is and figures that his 2028 presidential election campaign and high tech stuff might become irrelevant very fast once the nukes start flying.