Category: Intervention idea
Epistemic status: speculative; arm-chair thinking; non-expert idea; unfleshed idea
Proposal: Have nuclear powers insure each other that they won't nuke each other for mutually assure destruction (ie. destroying my infrastructure means you will destroy your economy). Not accepting an offered of mutual insurances should be seen as extremely hostile and uncooperative, and possible even be severely sanctioned internationally.
BTW, I have recently learned that ICJ missed an opportunity to explicitly state that using nukes (or at least a first strike) is a violation of international law.