First of all if you all think that SFC will actually wait for Pakistanis to use nuclear weapons and then retaliate, then you all are seriously mistake. Our NO FIRST USE policy is focused on countries that are NOT armed with nuclear weapons. At least this is what the treaty's main line is shown to the crowd in many articles and even Wiki. This means that the NO FIRST USE policy is only a piece of paper should a nuclear hangover occur. First of all, no one will use nukes. If Pakistan uses it, it knows that it will cease to exist and 180 million people will vanish from the face of this earth.
Any significant attempts to take over our land by any bigger power will be met with nuclear strikes on their capital which means, we take them along with us (in a fictitious scenario) and most of those powers of such intentions are aware of this fact; or else we would have been conquered long back. The only real and possible scenario that we have to look out for is the imminent collapse of Pakistan which is happening as we speak. Even out intel chiefs have been quoted saying that "we just need to sit back and watch the show".