Elements of the Ukranian government have apparently sort of quietly hinted that if they don't receive sufficient conventional military aid then they'll be forced to develop nuclear weapons as a last resort. Ukraine has officially denied this, but it's impossible to know how they'll react as Russia conquers more and more territory. Ukrainian leaders are quite aware that the only meaningful guarantees of continued sovereignty would be NATO membership or having their own nukes. Otherwise even if the current war is settled with some sort of truce, Russia could just rearm and attack again in a few years.
https://www.newsweek.com/russia-ukraine-nuclear-bomb-1985621