The difference between peacetime and wartime readiness for nukes only relates to tactical nukes; at least when it comes to an competent nuclear power, nuke are always at the ready at a moments notice. They launch nukes, we launch in retaliation, major destruction spread out over large swaths of land, both sides nuclear capabilities are gone (other than subs that were already deployed and didn't launch their payload). U.S. sails into the Black Sea.

Nukes aren't designed to stop navies.