It should be crystal clear to everyone by now that Putin is bluffing and is full of shit on every threat he issues.
Red Line, Red Line, Red Line, Red Line, Red Line
All crossed. Whenever the West crosses one of Putin's ridiculous red lines, he folds, because he is bluffing and has nothing he can respond with that doesn't guarantee his own death, of which he is terrified. To everyone's detriment, the West has fallen for Putin's bluffs for decades. It's time to stop and recognize that Putin is in a weak position and he doesn't have any strength to act out with, or he'd have used it already.
Short of NATO invading Russia, which isn't going to happen, Putin is not going to use nukes. He's not going to do shit. He can't, or he already would have. Even setting aside the fact that he doesn't seem to have tight control over his military and they're likely disobey an order to launch nukes, nukes guarantee a sizable western military response, possibly Article 5 depending on fallout. They also mean being cut off from everyone, including India and China for the foreseeable future. Either way, that's the end of Putin in power and likely ends with him getting something along the lines of a bayonet enema like Gaddafi.
If the West provides Ukraine with the rest of what they need to win, Putin is going to fuck off back across the border, declare victory and try to rebuild what's left of his powerbase.
Dictators and bullies only respect strength and they incessantly attack perceived weakness. Lets give Ukraine what they need to throw the Russians back to the pre-2014 borders.
It also sets the perfect tone for China on Taiwan. FAFO.