It depends on what comes up before the council, but China probably wouldn't veto it. They've been noticably quiet (tehy barely issued a statement on the matter). They are North Korea's biggest trade partner, but the Western World is a far larger partner. When it comes down to it, they aren't going to want to side with a blatant militarily aggressive state.
Hell, China is more likely to take military action against North Korea than South Korea is. The last thing they want is a US military presence pushed up against their border like that.