First, there are some credible analysis on Nasr in this forum, Indian soldiers won't parade inside Pakistan in a nice square formation, they will be spread across a large area, the number of Nasr that will be required to destroy just one tank battalion will leave the most habitable, densely populated, and fertile lands of Pakistan on its eastern border useless for hundreds of years.
Second, because of the sheer differences in size and shape of India & Pakistan, Pakistan will be completely destroyed before it manages to destroy enough of ours to make our country nonviable. Due to that long narrow shape of Pakistan, all parts of it is within the range of our smaller missiles and radar system.
However, good luck for a nuclear war if that is what you are looking for.