The Exocet is a French missile. There are a few versions. The Exocet SM39 is sub lanched. It is carried by French subs (Rubis/Amythist class SSN's, Agosta SSK's, and Triumphante SSBN's). It is also carried on the old Daphne class SSK and newer Agosta SSK of the Spanish, Portugese, and Pakistani navies.
The Exocet SM38 is a ship and air-lanched version. It gained notoriety during the Argentie war when the Agentine Navy Super Enterdes used them to sink some British ships. Likewise Iraq mounted them on Mirage 2000's during the Iran-Iraq war. One of those fired on and hit the USS Stark.
Finally, there is the Exocet SM40 which is a more advanced and longer ranged ship lanched version.
The Exocet SM39 has a conventional shaped charge warhead.
I doubt Pakistan has the advanced miniturization technology to make a small warhead. The warhead would have to weigh under 1000 pounds and be smaller than 21 inches (533mm) around.
The Soviets and now the Russians use nuclear anti-shipping missles.
I don't know if India has puchased any Klub ASM's for its Kilo 877EKM's. India has at least one Charlie class SSGN with its SS-N-7 asm.
http://www.globalsecurity.org/military/world/india/navy.htm
Past tense. India operated the Charlie for only 3 years, 1988 to 1991. The Charlie in question was leased to India towards the end of the expected core life span and India didn't want to pay for the refueling. There has been a stated, ongoing program to develop a domestic nuclear powered submarine program but that has never panned out.