But this is absurd logic. By this reasoning any crackpot can get want they want just by brandishing nuclear weapons. There is a well accepted answer to such nuclear extortion. It is well understood. It's called "mutually assured destruction." Anyone who uses them is assuring their own destruction. This is the reason the U.S. maintains a nuclear arsenal.
Mutually assured destruction as worked flawlessly to keep the world safe from nuclear weapons being used again. We won't ignore Putin's threats of course. So far, our intelligence services have been amazingly accurate re Russian plans. (They Russians have reportedly planted explosives at the Zaporizhzhia Nuclear Power Station that they occupy. This is a far more realistic concern then any threat of nuclear weapons.) We have been clear in our messaging to Putin, a specialist in brinksmanship. He knows what will happen if he uses nuclear weapons in Ukraine. Therefore he won't use them. Of course, people can go absolutely bat shit crazy. No real danger there either, because no one person can obtain, deploy and detonate a nuclear weapon. We have plenty of real threats to worry about without being afraid of our own shadow.