Generally, most likely yes, modest escalation of some sort. But he's made some bad decisions in recent years so I'm less comfortable with relying on his rationality than I was in the past. Remember, Vlad is actually a moderate in RU, there are many folks well right of him (and right of Ghengis Khan) who have already advocated for the use of tactical weapons in UA. And he has to thread the needle between the hard-liners and NATO.

If nukes get used, it will be in UA at a tactical level and will most likely have the same result as the last two nukes that got used... immediate unconditional surrender, since UA's nuclear armed allies will not dare escalate.

I was also surprised that whoever is running the white house allowed this. I've been generally in favor of supporting UA with materials, if they want to keep fighting, but this wasn't necessary given the pending US regime change. Literally just poking the bear.