If NATO invades, Russia is doomed. Putin doesn't care that Russia would still exist after a NATO victory, all he cares about is himself and his legacy. Both of which would be destroyed in a NATO victory.
So he would launch the nukes and watch Russia get wiped off the map, because if he can't have it, no one can. And at least he would go out with a bang, rather than suiciding in a bunker.
The oligarchs would not be able to prevent it. They might hold the political power, but the military order to launch the nukes comes directly from Putin. The best we could hope for is conscientious officers refusing the order.
Yep, I agree. But Putin has held on this long while he has royally screwed the Russian economy, and exposed their bumbling military for what it is. The oligarchs would have ousted him already if it was easy.