While it's not possible that Putin will do that. Dropping a nuke will only make more enemies for Russia and there might be no diplomatic talks anymore. This will just trigger the nuclear power countries to go to war when right now they are just looking away. He is already winning by just choking the gas supply. The skirmishes are what he will do since it's about who is going to last long as sanctions take effect. Putin will not do it, he does have a strategy for everything and thinks of consequences.
no it won't putin will justify it with same situation like the US with japan, why should he allow this to escalate the woke west will go after china with same manners like they now go after russia, they will not respect state authorieties they don't mean anything for the woke corrupted west.
Let me guess, he will say that Ukrainians did it on themselves, and Russia will open an investigation and prosecute responsible Ukrainians.