Funny that my 2000th post is about a nuclear holocaust, but here goes...
India has a no 1st use policy which means that in all probability if there is a nuclear exchange between India and Pakistan, it will be initiated by Pakistan. Unless Pakistan conventionally beats India down and is about to capture Delhi
rofl
Now despite a lot of Pakistani members on this board (most of which are living away from Pakistan) believing that one day, Kayani will get upset with Manmohan Singh and lauch a nuke attack on India, this situation will only arise if India has actually captured large parts of Pakistani territory and is about to over run key strategic locations like Islamabad, Karachi or Palkistan's strategic assests like Nuke storage locations or Nuke reactors (extremely low probability)..
Now from a Paksitani mindset, the intent still would not be to commit suicide. At this time, the plan would be to escalate the war so as to enforce a cease fire thru international pressure. Now Pakistan would know that if they take out Delhi or Mumbai, then no matter what the international pressure, India will turn Pakistan's cities into radioactive dust.
However the resolve of India may not be so rigid if the attack was on say the Western command HQ or similar targets and will have a higher probability of showing restraint in retaliation assuming its assured of strong enough punishment (like Denuking) for Pakistan for being the nuclear aggressor
Now if there are miscalculations and Pakistan decides to go after Indian cities from the word go, then you have your worst case scenario.. Or if India does not take the 1st attack (despite being on a military taget) lying down and razes some similar structure/location in Pakistan and the escalation takes place, then again its back to worst case scenario.. But my take is that the 1st option of 1st strike by Pakistan followed by International intervention and denuking of Pakistan will be the most likely result of a nuclear war between India and Pakistan.