ok, I generally go conquest victory.... So I will use nukes. That said, a tatical nuke rocks for taking out a stack of... well... any military unit including battle ships! and yes I have used taticals for taking out battle ships.
I would not open with nukes and I would not use nukes if you want a diplomatic victory. However, If your going for conquest, prep 1 tatical + nuke sub for each city of an island enemy or just one tatical for each city he had near you... nuking most of your enemies cities, will permantly blunt his offensive.
That said, I was playing aztecs and I did not actually break any rules such as declaring war before 20 turns or canceling an agreement within 20 turns due to war... BUT the greeks declared war on me and proceeded to nuke me every 2 - 3 turns... It sucked. BUT I built a ton of workers...
I guess what I mean is if your being nuked, you need to take out that guy fast. If you want to nuke that guy, your going to have to fight another civ shortly there after.