He may not use them offensively as you say, but if his invasionary forces were pushed back at the southern boarder by a coalition, he may well decide to light one off on that boarder as/before he bugs out. In the notion of; if I can't have it, no-one will. These kind of people are just school yard bullies who were never taught to play nicely with others with the resources of a nation state. It will be quite interesting to see how other nations that currently support his regime react over the coming weeks.
I would also note it would only take a few more incidents in different areas of the world in which America has vested interest, to really start stretching their military resources. They say don't poke the tiger, but currently the tiger is a little busy and ripe for the poking.
I'm tipping sanctions, sanctions, sanctions. What other non militaristic options do we have? Problem with that is it wont be Jong-On and his cronies who starve or go without. And since the citizenry are little more than props of the state, they will make great propaganda TV to whip up more hatred as they die in the street because evil China / Russia / South Korea / everyone else wont give them any food. And since there is basically zero incentive to innovate or invest in any kind of agricultural endeavor, because, as it turns out, socialism and juche results in basically zero incentive to innovate or invest, they cant feed themselves.
However, due to the governments Songon policy, we might see 24 million regular, if somewhat malnourished army shortly.