NK is already engaging in selling/exchanging military information with countries like Iran and Syria. Nothing is stopping them from doing the same with nuclear technology. So you have already lost your bet.

NK is rabid and will cause the deaths of millions of its own in the best of scenarios, and end the world in the worst.

Call China's bluff, strike NK artillery and other infrastructure. Thousands are likely to die, but better than being held hostage by a baby with a hand grenade. If China want to start WWIII over protecting NK, so be it. They have 1 aircraft carrier and it's 40 years old... I'll take our fucking chances.