Putin isn’t going to nuke Ukraine cities because that makes his whole invasion pointless.And if I were a Ukrainian, I’d be pretty pissed off if the Russians nuked the fuck out of my city because a foreign country made the wrong decision.
Kyiv is seen by him as the birth place of the Orthodox Church and a jewel in the Russian Empire so he won’t nuke it.
I personally don’t think he will nuke anywhere but I appreciate some are more worried.
But, the Ukrainians are begging for a no fly zone and NATO support on the ground so they obviously want to take the risk.