North Korea already had enough chemical weapons and biological weapons and the missiles to deliver them to kill everyone in South Korea and take a good piece of Japan, Manilla, Beijing, Kamchatka, etc. along with them.
The biggest problem with nukes is that a couple of missiles can now some of the same damage a thousand missiles would have done before.
Some of Jong-Il's Nodong missiles could probably reach Hawaii (and soon perhaps the continental US) (and LOL at that "I have Nodong" cartoon.)
Then there is the chance that NK would transfer them to someone (like an Osama for instance.) Just last week, it was proven that NK illegally sold uranium hexaflouride to Libya. Not a big step to sell enriched uranium or plutonium or an actual nuke.
Did you say North Korean missiles can reach Beijing????Well,NK has it's missiles,nuke programme & it's "independence" because Beijing wills it.NK & Pakistan have got help from the PRC so that it's regional rivals like Japan,the US & India remain tied down.The moment the PRC moves away from NK,our peerless leader will be consigned to the history books & China will lose it's most trusted insurance policy.