It’s hard to guess!!! North Korea is a rogue nation under the leadership of lunatic Kim Jong Un. What it does with its nuclear weapons largely depends on its own agenda, as well as others countries’ policies in regards to North Korea.
It’s no secret that the N.Korea’s leadership has always been the enemies of USA. So if they do decide to trigger the button, it is America that’s most at risk. And the situation between the 2 countries has been worsening ever since Donald Trump came into power. There is a lot of heat between these two right now with few experts are believing that this could trigger World War III. If that happens, we could see turmoil on a global scale, with economic imbalance widening and development hampering in many countries, thanks to the allies of both USA and North Korea jumping on the scene. And of course the countless loss of lives on either side, which North Korean leadership would hardly care about, given they starve their own population.
However, these are pure speculations as of now. The world has come a long way since 1940s. We have good measures, strong communication and better policies that can counter the rise of any global war. So the war between USA and North Korea is quite unlikely as of now—because both know the repercussions. Although USA, along with other countries, has been hammering North Korea economically with many sanctions!
So what North Korea will do with nuclear weapons that it has been developing (and proudly showcasing) is yet to be seen. The idea of war is there but it’s unlikely. If everything goes properly, if both keep their heads calm (which is possible only after the change of their leadership), and if China, South Korea and UN, in particular, do their part correctly, the nuclear weapons of North Korea will probably run dry.