Let's say the US balkanizes, becomes decentralized and finally stateless. What to do with the nukes that were left over? Who controls them if there's no central power? Obviously, there should just be no nukes, but let's say other countries that are still states have them, so would it be prudent to denuclearize?
In the spirit of anarchism as a tension towards peace, disarmament is the goal. In the reality of anarchism as self defense against structural violence, MAD would probably hold for a while.