It is rather interesting that the US will not accept North Korea, a country that hasn't invaded any foreign country ever, as a nuclear power, while the US themselves are "acceptable" as a nuclear power, despite the fact that they habitually invade foreign countries every few years for the past century, and having already used 2 nuclear bombs against civilians.
A nuclear capable North Korea with it's current unstable and irrational regime is in the interest of no one. It also poses a direct threat to South Korea and Japan, and by extension to their allies as well.