There was lots of discussion within Russian and Ukrainian war analytics that nukes (at least tactical) are useless in this war for the following reasons:

- they would not change much on battlefield - there is no large concentrations that you can nuke - everything is dispersed

- nuking urban centers again won't change much on battlefield but would alienate China

- Russia's equipment is known to be not most reliable/maintained and worst that can happen to Russia is them trying to nuke and nukes not working