I expect Russia and NATO will only use tactical nukes as escalation if the need arises and in Russia's case if Russian state is threatened. I think it is plausible that Russia could leave the Western Ukraine nationalists as a problem for the foreign authorities to handle. US has made noises recently about a korea type "solution" and that increasingly looks like US best option.
Warhawk Witch of the West - Nuland is not happy and is doing media recently promoting the idea of using US long range weapons on Russian soil but her disaster Ukraine project to topple putin got her fired and she is on the outer now. I dont know how much influence she retains on the inside of the Biden admin with an election approaching.
