No such thing as a flawless victory. But I can guarantee you that million men army of North Korea won't be staying a million in short amount of time even with all the intelligence provided by China.
As long as North Korea is developing and improving their ballistic missiles with nukes, the U.S. ain't standing still, doesn't matter if it concerns China. Actually I think China is rooting for North Korea to be able to hit the U.S.
That be equivalent to giving nukes to Japan, Vietnam, Philippines and South Korea.
To North Korea, a ballistic missile is way expensive. To us, loosing a city is even more expensive than two missiles to destroy one.