The Permanent Representative of China to the UN has deposited the country's instrument of accession to the treaty to Secretary-General Antonio Guterres.
There are probably small scale things that North Korea might request behind closed door, but ultimately, North Korea would be speaking things like a peace treaty with the United States and South Korea.
Administration feel that a peace treaty is the kind of concession that should come near the end, after North Korea has already given up a substantial share of it's nuclear arsenal.