Well they might talk to Taiwan.
If they rattle the nuclear saber they should assess how the other nuclear powers are going to react.
One could make the case that to counter balance the threat of a nuclear North Korea we should station or allow friendly local countries to have their own nuclear arsenals. South Korea, Japan, Taiwan, and the Philippines come to mind.
Perhaps the mere threat of a nuclear Philippines and Taiwan will give China cause to be more persuasive in its suggestions to Rocketman?