Sort of. The UN Security Council refers cases to the International Criminal Court for prosecution [1], and the ICC, both present and historical ad hocs, is a creature of it [2]. China isn’t a state party to the ICC, which limits its jurisdiction, and vetoes UN criticism of it, so pointing to either of these bodies as exonerations is tantamount to asking Beijing is the CCP is committing genocide.
[1] https://en.m.wikipedia.org/wiki/Uyghur_genocide