I should clarify, I totally agree it makes zero sense, and the odds of Russia actually doing something like that are low. But invading Ukraine also made no sense and here we are, so I'm not giving Putin the benefit of the doubt when it comes to strategic decision-making.Where is the benefit? The Ukriane army/military doesn't seem to fight in large battalion sized groups. I'm sure their military is probably composed of such groups structurally but they certainly don't seem to fight on mass like the Russians do. Maybe I'm missing something but I've litterally never see a single video of their forces moving in large columns like the Russians do, which makes for easy ambush targets when performing offensive maneuvers. It seems pretty obvious that they avoiding moving en massw like that to avoid being easy targets for Russian air and missile strikes.
A tactical nuke is most useful when facing and outnumbered by a large mass of troops and armor. As awe-inspiring as nuclear weapons are I don't see a how single nuclear bomb, especially only a smaller tactical one changes the overall course or narrative of the war in any situation for the Russians. Yet the use of one is a huge provocation and is much more likely to be crossing Nato's red line as well as losing the support of Russia's few uncoerced allies. Would China and India just be total fine and ok with Russia lobbing nuclear bombs around? It seems like such a play and the reverberating effects of it is a much more riskier propostion than its worth, and makes no sense while Russia thinks it can still win conventionally. That's disregarding all the negative on-field effects, it would render the area uninhabitable from a strategic stand point for some time and worse yet Russian forces or cities might actually suffer the brunt of the radiological effect depending on how close such an attack is to their positions/land and which direction the wind is blowing. The contested regions seem much too close in both respects for that action.
That said, my original point was simply to highlight the scenarios in which NATO could get drawn into the conflict and what that might look like, it was not trying to imply these things had a high likelihood of happening.