I think that you're confused here.
Ukraine has already been attacked by Russia with a nuclear-capable medium-range ballistic missile (MRBM) - while Russia has not.
And the Ukraine is the only country being attacked by actual boots on the ground from TWO nuclear powers.
I'll begin taking Russia seriously when they succeed in regaining their lost territory in Kursk oblast.
Maybe also when at least 70% of their people have running water and indoor toilets.
Regards,
I’d add that Russia has used thousands of “nuclear capable” smaller missiles on Ukraine, so far, by their very own statements of missile attacks made. And ATACMS and Storm Shadow are shorter range than many of the Russian missile, AND ATACMS and Storm Shadow have been ok’d for medium range use only in Crimea and a small area around Kursk.