Absolutely they are!! Only crazy people could call for a nuclear weapon to be used against other human beings!
But, wait...
Oh... I see...sorry.
If Zelensky would have had nukes in his arsenal, we all would be balls deep into a nuclear war long ago.
I honestly think, or want to think, that NATO and Russia are working into some kind of peace pre- agreement, western countries may have gotten already what they wanted: big bussiness have been done and the russian army has been severely damaged by now. Russia, perhaps, could accept to keep control over Crimea, Dombas and maybe a land corridor inbetween. Problem now is the ucranian role here.
Ucraine had not choice but to ask for western help, but they knew all that help was not for free, they knew that they were trading sovereignty for weapons, and now they see how they only have a decorative voice in the potential negotiations. So they will probably try and avoid them to succeed.
These misils in Poland seem a good standing point. No confirmation of the russian procedence, even if confirmed, there is still no evidence about Russia voluntarily striking Poland, (willingness is key: in 1999 a NATO bomb destroyed the China Embassy in Belgrade by mistake, apologies were given and it all ended there) but here you have Zelensky urging NATO "to act", that is, to start a nuclear war over the incident, no need for further investigations or apologies, let alone an agreement. Just "NATO action", nuclear war is the only solution he foresees.