U.S. BMDS Causing Nuclear Explosion?

Would using a U.S. BMDS to shoot down incoming North Korean Nuke missile cause the nuke to explode in the air if it was shot out of the air?

U.S. System link:
www.mda.mil...

North Korean weapons link:
www.globalsecurity.org...

What would happen to the nuclear weapon itself, would it just break up into pieces in the air or would shooting it down cause it to explode.

Does anyone know if we are actively, preparing to go to war with North Korea, after they said sanctions would = war.
Or are we just sitting around and waiting for something to happen, seems to be not that much info. as to if we are preparing for the worse, does anyone have any more info. regarding this topic?

PHARAOH1133