Your entire history will be decimated by our Strategic Command Force if you decided to launch a nuclear strike on our soil...
We can do WHAT-EVER we want on OUR soil...Your forces must stay on THEIR soil...simple as that.
PS. indians would be the most retarded people if they decide to commit a nuclear-suicide over 1 brigade loss on enemy's territory or something...
first some background:
First India is not interested in launching or taking over Pakistan lands. India is much happy if Pakistan prospers and becomes like Canada and a prosperous and peaceful and friendly nation with open borders with India.
India knows Pakistan can use tactical nukes on its army if it goes inside
Now to the main point,
So clearly If India do actually decide to go in and invade Pakistan lands then it means Pakistan has done something very very nasty which is NOT IGNORABLE (what it might be is anybody's guess). So Pakistan has already done something which India cannot ignore come what may. So India is left with no other option but to go inside.
Now when India would have decided to go in India would be fully ready to launch a counter nuclear strike. (whether full or partial or what doctrine will they follow is open to debate). But yes India would have a READY plan to Nuke back and it would be in a high state of readiness before Indian army enters Pakistan. India would have already decided what STEPS it would take in case of tactical nuke strike on its army.
Now if Pakistan launches a tactical nuke, it wont come as a surpirse to India as they would have already figured it out in their battle plan and they knew the risks beforehand. So if they decided to go in even after that, it clearly means they have taken that risk into account and have put in risk mitigation measures for it. It means they are ready to face the situation of being attacked by tactical nukes, and have put in counter measures to both AVOID/NULLIFY the Tactical nukes if possible, and if that fails and the tactical strike is a success, then also they have counter measures to deal with it.
But what Pakistan don't know is what would be the India's response and India's counter attack strategy if the Tactical Nuke strike is a success. Now that is a huge risk being taken by Pakistan armed forces. But using the tactical Nuke on India would ensure one thing - that India would have now ALL OPTIONS OPEN on the table and no body in the world is going to object to any option being used by India. I think this would leave India in a big advantage.
While India would have all options open, Pakistan would be left guessing the next Indian move. But rest assured that if Indian army do decide to go in to Pakistan, they definitely did not do so to stop in case of being attacked by a tactical nuke. If they planned to stop on being hit by a tactical nuke then there is no point in going in at the first place. So that means a successful tactical strike wont mean that India would cease war there. The only question would be what would be the response, but the war would continue. Tactical strike wont lead to ceasefire.
Another scenarios could be that India has its own tactical nukes. The armed forces would be suported by tactical nukes while they enter Pakistan. The major Pakistan Army installations would be the target of the Indian tactical nukes. Brahmos and Nirbhay can deliver the small yield weapons with great accuracy to any facility of PA. So when India sees its brigade being attacked by Tactical nukes, the response could well be use of same Tactical nukes on PA facilities and formations. So in all all the nukes land in Pakistan lands only (albeit low yield tactical ones and on military formations/facilities only). But in this scenario if both sides use the Tactical nukes against each other inside Pakistan only. I think IA would come out victorious without any doubt.
So these could be few of the possible responses by IA. But the planning would be done in advance to counter a tactical nuke strike inside Pakistan and suitable counter risk measures would be employed both before the strike and after the strike. Entering Pakistan would mean India would have accepted the possibility of Nasr attack buu they still decide to enter, because maybe Pakistan has done something which is absolutely beyond the red line. So at that POINT the Nasr wont stop the IA or the war. The war would continue beyond the use of Nasr (failed or successful).
If Nasr doesnt stop India from Indading Pakistan land at the FIRST PLACE (which means use of NASR is not required at all), then if India do enter Pakistan then use of NASR would not stop IA (which means even if NASR is used it will not stop the IA and NASR would be useless to stop the IA). So the deterrence of NASR may be useful but the use of NASR would be useless.