Make no mistake, the DPRK's nuclear arsenal is not just a toy set Kim Jong Un plays with for his amusement; he may very well intend to deploy it against the US, South Korea, Japan, or other Western allies. If Kim continues his reckless pursuit of posturing on the global stage, he should understand that the leaders of the free world will respond in kind.
The West's zero-sum approach toward North Korea has been a failure for almost the entire 21st century. The US can no longer demand complete denuclearization while simultaneously conducting military drills in Kim Jong Un's backyard. As the Korean War never officially ended and the DPRK is still an enemy of the US, Kim will continue to feel threatened until Washington decides to offer something more substantive.