Petraeus: US would destroy Russia’s troops if Putin uses nuclear weapons in Ukraine https://t.co/KXrhD7RVKo
— The Guardian (@Guardian) October 2, 2022
Might just be political rhetoric, and worth bearing in mind this isn’t a US government position, but considering recent battlefield developments and the effectiveness of Nato weaponry versus Russian/Soviet ones it seems plausible.
Then consider the swift advance Ukraine has made in Kharkiv compared the the grinding advances and attritional tactics of Russia in the last few months. The recent Battle of Lyman and ongoing Battle of Bakhmut are examples of this.