There is precisely no chance whatsoever of Putin using nuclear weapons except in the most limited battlefield-specific capacity - and even then, whether or not Russian officers would actually carry out such orders is highly debatable. Multiple times in the history of the cold war, Russian officers breached rules & regulations in order to avoid launching nuclear weapons, even when it appeared the USA had carried out a first strike. Today, the chances of Russian officers voluntarily consigning their families and friends to annihilation is even smaller than back in the days of the USSR.

Putin threatens to use nuclear weapons merely because he - correctly - assesses Westerners as stupid, fearful, and easily fooled. But even Putin, dying of cancer and doped up to the eyeballs on happy pills, doesn't want to end his time on Earth as a pile of radioactive ash.

Only our folly, simple-mindedness, and sheer ignorant stupidity leads us to imagine that global nuclear war is even vaguely likely.