IMHO There are a lot of "ifs" concerning the NK's.
It won't be like Afgan. Which had/has no techey stuff. No planes, no tanks, no artillery. Just AK 47's and IED's. More guerilla stuff, not government backed, then standing army with a government.
Not like Iraq, where the government backed standing army, what 7th in the world at the time, with planes, tanks etc. surrendered in mass. Which was weird and unexpected.
NK stood their ground pretty good the last time we went in. It's part of the reason we got an Armistice instead of a victory.
China did help them, then. Will they do it again. Another if.
Nukes, there are lots of "ifs" on that, will they use them, launch them, ship them, send them underground in those tunnels......lots of 'ifs'.
If it doesn't happen fast, and get over fast will we stay? If the body count goes to high will we stay?
I think the only thing that won't be an 'if' is, it won't be easy.
I also think the only thing we can't let them do is acquire an ICBM. Pre-emp if we have to. Them having nukes is bad, but I hope we could interdict there movement outside of the country. Meaning shipping to Iran, in a fishing troller going to San Fran. etc..