The idea here is to blend in the launch vehicle with the normal battlefield ones (MBRLs/Transport Trucks) therefore it would be difficult to spot the launch vehicle. Pakistan could've modified a few Ghaznavis with low-yield warheads for the same role (as they are pretty much accurate too), but a MAZ-543 vehicle is too easy to spot for satellites. Moreover, the true meaning of the message i.e. possession and potential use of tactical nuclear weapon could not have been conveyed by merely stating that Ghaznavis have this capability.
Nasr is Pakistan's attempt of preventing conflict escalation at the battlefield level.
it wont work that way.
The use of nuke would NECESSITATE a strike from India. 20000 or 30000 Indian troops killed in a Nuke strike? Do you think India would or could afford to not respond? So let me say without doubt that yes India would respond to use of NASR. Now the question is what kind of strike it would be. I think India would not attack the civilian cities but India would launch preemptive strikes (both conventional and nuclear depending upon requirement) against all PA/PAF/PN bases and missile facilities. After this India would again send forces to invade Pakistan fully.
In-fact there would be a world wide concerted effort in that case to snatch or disable or eliminate all the Missiles and Nukes of Pakistan. It is also possible that US, Russia may also attack Pakistan from their subs and precision weapons/missiles to eliminate Pakistan missiles and Nukes forever.
The out come of NASR would leave no choice but to force IA and world to invade Pakistan. NASR would not result in protection of Pakistan but would force India and world to invade Paksitan and ensure that in future there is never a possibility of any nuke being launched from Pakistan soil. So instead of saving Pakisan, NASR could and most probably would have the opposite effect and lead to the invasion of complete Pakistan by US, India, Russia and others.
The world doesn't like the idea of a country which has nukes and is ready to use them at short notice. So it is a real possibility that Pakistan Missiles and Nukes would be taken out and Pakistan would be invaded if it used Nukes in any form against India.
So before NASR is used, IA may not invade complete Pakistan and also its missiles and nukes may remain intact. but the use of NASR would ensure and necessitate that
1) Pakistan is indeed invaded completely
2) All the missiles and nukes of Pakistan are disabled/destroyed/captured
3) Pakistan is never able to use a Nuke or Missile against any nation again
But at least one thing is clear, that if Pakistan attacks India troops with Nukes and kills 20000 to 30000 of India troops
there would definately be a response from India.
The only uncertainty here is what kind of response would it be. But anyone thinking here that after the use of NASR India would not do any attack and stop the war is massively mistaken. There is only one certainty here and that is the use of NASR would invite a Indian response and not lead to the end of conflict as it is being thought. NASR would lead to prevent battlefield escalation is very wrong notion. This thinking is equivalent to the thinking that attacking India across LOC would never invite Indian retaliation across IB. that is basically such reasoning has no basis and if it has any basis one possibility could be based on some flawed and stupid concepts of peaceful or weak nature of Indian resolve
So let me conclude by saying, 1) that if threat of NASR is not able to prevent IA from entering across IB deep into Pakistan, the use of NASR would never lead to a stoppage or deescalation in war. 2) use of NASR (if used once India has crossed IB) would not prevent but necessitate and precipitate the invasion of Pakistan.
thats my sincere view of what NASR would result it. please others can differ.