Probably silence, since China can veto any security council resolution, and a lot of the countries in the general assembly probably don't care to make waves (if they even care at all) since they want Chinese money.

Why would the UN have a stance on this?

It's been hugely magnified the media, but it is no more than a government bringing a bill forward and people demonstrating against it.

This often happens in most Western countries and no-one asks the UN what they think about it.

Perhaps time to put things into perspective.