One thing is off. After NASR strike by Pakistan India will retaliate but Modi will not be sitting around giving press conferences. He will be in a nuke proof bunker.Yes it is possible for nuke strike in delhi and other cities but the entire top brass of GOI (as well as GOP) will be protected.
Additonally the first nuke strike by NASR would be detected by international community and within minutes phones in Delhi and Islamabad would be ringing off the hook. India would likely to get a retaliatory strike on Multan but my assesment is that it will be probably last attack of war