The West will simply eradicate russian forces with conventional arms if russia decides to nuke Ukraine.
And there is snowball's chance in hell that russia actually dares to nuke NATO country, because it would guarantee the formation of What-Used-To-Be-Moscow Exclusion Zone.
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No.
If NATO does a pre-emptive strike at russia, that's it. The biggest negative would be having to live with having slaughtered tens of millions of russians.