For starters, the game theory discussion you are replying to seems deeply simplistic. Even if you win, you end up with a ruined planet (how many nukes would you need to neuter Russia?), are likely to end up in jail in your own country for doing so, and worst case scenario you fail to wipe out some nukes and then you are even more screwed.

Now, about your point... given on the info he had, Putin thought he was able to rush Ukraine, obtain a fait accompli, and then the sanctions will stop. He didn't knew his army was so bad (dictator's bias and all that), and he cared about his image for posterity, not about the wellbeing of Russia itself. In that case, war was anything but unlikely.

But about the bombs? What does Putin gain with a tactical nuke?

a) It somehow fails during the flight, or fails to detonate = Humiliation b) Soldiers refuse to pull the trigger, he gets a rebellion. c) It explodes, he manages to wipe out 1-2 battalions at most, so it doesn't change the outcome of the war. OTOH, Russia becomes a pariah state and gets blockaded hard (potentially even by China/India), Ukraine gets every weapon they need, and they risk actual NATO intervention.

None of the options improves his own outcomes, so I don't think nukes are as likely as news/reddit posts make it look like.