Yeah, Kim ticked off Chinese, who can choke his regime to death. China is now doing slow strangulation, a la anaconda. For example, Chinese drastically cut down food aids since last spring. If China ever completely shut down oil and food, N. Korea would most likely go down.
Chinese would only do this because they fear Japanese and Taiwanese nukes.
Re: "Chinese would only do this because they fear Japanese and Taiwanese nukes."
That fits in with my armchair analysis. North Korea with nukes is of no advantage to China. Like you said, it is only encouraging South Korea, Japan and Taiwan to go nuclear also.