And even in that case use of nuclear weapons would be unacceptable escalation and they used regular army to (mostly) kick them out and carry on with their earlier invasion on other parts of the front.
(I am speaking about Kursk if anyone is confused)
Use of nuclear weapons when you are mildly threatened is not viable. In the same way as responding to a pickpockets with an artillery barrage is not viable.
"We do not need police as we have an artillery" is equivalent of "there is no need for any other weapons if you have nukes".