Honestly, I'm not sure what Corbyn's views on MAD actually are. He deliberately dodges the questions but Labour already committed to renewing Trident, no? I'm thinking he may just be avoiding the 'yes' answer because he's trying pretty hard to attract the youth vote, and he'd lose most of it instantly if he said anything like that. The naive youth weren't around during the cold war so they just see nukes as nothing but a killing tool, they don't care for any tactical capabilities having them gives us.
I may just be giving him too much credit, though.