Putin's Nuclear War

Putin wants to raise that old specter of nuclear war, but it can't be done with any details. If he decided to use overwhelmingly tactical nukes to invade Ukraine and go all the way to the Polish border, will create a World War III? Second option, he could decide to go on an Airbus or a, you know, Kieff, for instance, to kill a lot of people. I don't see the point at the moment. It will make no sense.