Interesting war gaming
We know where it may hit within a relatively narrow band. But we don't know where within that band. Because the Earth and the asteroid are moving so fast, we need to have the timing precise to minutes or less to have an idea of where it will hit (if at all).
I strongly doubt that Iran's military capability can be destroyed by a single untargeted 8 megatonne airburst.
China's _obviously_ cannot.
The absolute worst case here is it goes off directly over a city (though, naturally, this is extremely unlikely, most of the world's surface not being covered in city). It's not a country-ending thing.
The more interesting question in pertinent scenario is whether countries will prevent asteroid deflection if it increases chance of randomly shifting impact to them by some %. I surmise no one will do anything to save someone elses ass, only their own, i.e. US saving India's ass but fragments end up over PRC and kills someone... congrats, just started WW3. Countries powerful enough to deflect, will risk fallout to avoid impact on itself... since weak suffer what they must.
I guess we'll see if Sticks are still a thing we can fight with for WW4, but stones was definitely a solid prediction.