B54 SADAM -- Special Atomic Demolition Munition:
You think?
I count nine official nuclear weapons countries, but several others are suspected of having nuclear components ready to be assembled at a moment's notice.
And nukes have been built in all sizes and shapes, including so-called "suitcase bombs", perhaps better thought of as "backpack bombs", since they are literally man-portable.
Point is, I don't think Russians can start throwing their nukes at any other country on earth and expect to remain impregnable to all retaliations.
And Russians would not necessarily ever know who built the weapon, or how it was delivered, or when & where to expect retaliation.
Nor is nuclear retaliation the only potential response -- there are many non-nuclear responses that could cause serious and long-lasting damage to Russia's economy and capabilities.
My opinion is, throwing nukes would be the end for Russia as a nation and Russians as a people -- it would be a national version of "suicide by cop" or "Ukraine assisted suicide" and I doubt if any sane Russian seriously wants that.