My two cents' worth (not sure it's even worth 10 cents):
1. Iran and NK have been working together to develop offensive nukes
2. Iran had a massive infusion of money in the recent past; they could easily support NK's efforts to develop nukes, begging the question: is Kim really suffering? (Obviously, whether or not his people are suffering is irrelevant to Kim.)
3. China is probably putting pressure on Kim to deescalate, and well may dislike the idea of Kim having usable nukes.
4. Kim's nuclear mountain collapsed. I doubt that this destroyed his program, unless his paranoia meant that he didn't have backups of all the data.
5. Did his scientists die also? In that case, it could well slow down any development. If both 4 & 5 happened, it could pretty much end it for a long time.
6. Does Kim negotiate in good faith? Using information from past Kims and this one the answer is clearly no.
7. Is this a real opportunity for making NK nukeless? Yes, it very well could be.