Now since having nuclear silos are open targets for preemptive strikes Pakistan as well as Iran(chemical arsenal) need to devise strategies to increase the survivability of the equipment in case of preemptive strikes.
Iran does not have nukes so can emulate the 2nd strike options with chemical weapons although less effective but still deterrant.
1- This you already have. Say you have 70 nukes. just choose 5 of them and prepare the launch trucks. Load the launch trucks to warship. Warship is vulnurable but still a better option than a static land target which will be targeted by preemptive strike. In case of an attack warship unloads the truck to the shore which would fire the ballistic missile.
2-This option both Pakistan and Iran has which is launching chemical or nuclear cruise missiles from warships. This option can be developed further to be launched from submarines but launching from surface warships is already an available second strike option.
3-Ship launched ballistic missiles. Both countries should work on it and come up with a solution as soon as possible. It is a deterrant and in case stealthier warships are built the deterrance would be much better.
4-submarine launched ballistic missiles. Which is somewhat ahead of us or maybe developed secretly. Diesel engine quiet submarines although carry less should be the option. Since it is a deterrant measure it is enough and more stealthier than nuclear submarines.
I am sure usa tries to portray countries like Iran and Pakistan as threats as boogeyman that would invade the world and stuff. North Korea already claims to have submarine launch system. Is it because these are muslim countries that turns them to boogeyman. Then usa needs to do more for israel. The trust with us and our allies is not so fragile and we know that if it is not there then at the end usa will impose what we should like and what we should be afraid of as it is currently trying right now.
Also in addition to that surface launch of cruise missiles by submarines is possible which still has survivability of submarine. And firing of the cruise missile is easier when submarine surfaces above water.