In the unlikely scenario of a Nuclear War:
According to a report by Natural Resources Defense Council, India apparently has lesser nuclear warheads (about 35) compared to Pakistan (about 48) . It’s natural to assume that any nuclear war will lead to a lot of casualties and destruction. That said, both the countries do not have enough nuclear weapons to destroy each other to Ashes. Assuming that the following key geographical targets are attacked in both countries, here’s how the overall impact will look.
In such a post nuclear attack scenario, while India would have a slightly higher number of casualties, it will also proportionally wipe out a much larger picture from the Pakistani demographic. If there would be anything left for Pakistan to salvage by the end of it, India would still gain by having the advantage of a much larger military.