Putin is very unlikely to attack the west with nuclear weapons, because he knows that would be the end of Russia (and much of civilization).

He has other options - using a small nuke as a demonstration, or using one on a target in Ukraine. Even that would likely be met with conventional force that would devastate his army - raising the risk of escalation.

But people need to understand that nukes are not automatically world ending disasters. A global thermonuclear war would be very bad, killing hundreds of millions to billions

But a tactical nuke's effects, other than political, would be pretty local. If it were an air burst, it wouldn't even have significant fallout.

During the Cold War, the US military, and no doubt the Soviet, had nukes on almost every platform. My aircraft carried nuclear depth charges of all things - with a yield near that of Hiroshima (if you set the yield to max). Antiaircraft systems had nuclear warheads on the rockets. Submarines and anti-submarine platforms had nuclear torpedoes.

All of these nukes were tactical weapons, and low yield. But they were everywhere. And... not one of them was ever used.