We can never know for sure what Hitler thought. He probably knew war was going to happen soon or later if he wanted more lebensraum for the German people. But that wasn't known to the outside world.

But eh, have you ever heard about the cold war? Hundreds of nuclear weapons were used but not a single one got used, I wonder what makes you think that North Korea suddendly wants to use them on anyone.

And the USA isn't going to invade Asia anymore because they learned from previous Asian land wars they should never try such a thing again, especially in Korea.