Look at any other country that has given up its nuclear program. Khadafi, Saddam Hussein are here no more. Kim Jong-Un knows well too well that if he gave in to american demands, his regime will end.
This is an excellent article with more details on this : https://www.theguardian.com/world/2017/sep/08/in-the-court-o...
Still, that's an excuse to keep his nuclear program, not to try and capture Guam. Capturing Guam is a misguided goal, which could hint at a further addled mind.
It is always dangerous to use entertainment fiction as an analog to reality. Nonetheless, I cannot help but feel revulsion when a pampered, armchair sociologist tries to handwave the destructive tendencies of a poorly informed autocrat as some kind of grandiose, suicidal tendency.
The latest round of intercontinental saber rattling is not a product of rampant psychopathy; it is iteration of a proven methodology.
It's pure survival for himself and his dynasty, just like it was for King Jong-Il and Kim Il-Sung.
If the regime collapses and Kim brought to justice, he'll be executed along with any family members and anyone involved in the horrors the North Korean people have had to face.
He's using an entire country as a bargaining chip to ensure he remains in power, safe and protected from outside interference.
I'm not sure KJU is mad in the Hitler sense, but he's the narcissistic scion of a narcissistic pseudo-monarchy, and it may be unwise to expect rational foresight.