Putin upping his threats.
I believe no matter how many nukes he has, he is mostly bluffing, as he knows starting a nuclear exchange will be suicide for Russia - no matter what damages others incur.
I do not believe the Russian military high command would, at the last minute, sacrifice Russia for Putin. They’d rather have Russia intact than Putin, if they have to chose between the two.
Most of the German Generals were against Hitler, but went along with him anyway.