The Russian military in its current state is almost certainly unable to operate on a nuclear battlefield even though it has the necessary equipment and has historically trained its units to do so. The chaotic agglomeration of exhausted contract soldiers, hastily mobilized reservists, conscripts, and mercenaries that currently comprise the Russian ground forces could not function in a nuclear environment. Any areas affected by Russian tactical nuclear weapons would thus be impassible for the Russians, likely precluding Russian advances. This consideration is another factor that reduces the likelihood of Russian tactical nuclear weapons use.
https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-october-1
https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-october-1