That said:
While we all know that Russia isn't fighting all of NATO, it does claim that it is fighting all of NATO.
Do they believe what they say? I don't know.
I think if Ukraine attempts Hail-Mary tactics, if you assume the hypothetical that Russia really does believe that Ukraine is only capable of such things with NATO support, it is still bad for NATO.
There's certainly Ukrainians who want nukes now, who think giving them up was a mistake. Some say it would only take them months to get nukes… and they said that months ago. If they do develop their own independent capability, and Russia just assumes it's an American or French or British nuke, that's still bad for the rest of us, even if Trump is shouting about how the USA didn't do it.