You cannot eliminate ISIS with a nuclear bomb. Eliminate the bomb perhaps but not the organization.
I think ISIS is just like Nazism or the religious devotion the Japanese had to their emperor. Although you cannot kill all followers with a single bomb, a crushing defeat could well be what is required as a "reset event".
Their entire ethos is based on fighting a war at a certain level. Ideally, for them, directly with western troops which gives them an advantage and levels the playing field.
But they cannot fight using the weapons of state. They don't have them (yet, at least).
When the Nazis and Japanese were defeated in WWII, the followers were not immediately destroyed or converted. It needed years of education and deprogramming BUT the reset event was fundamental in shaking their world to such an extent that they were in shock and so could be de-programmed from the death cult they were in.
The reason it isn't appropriate with ISIS is that they have not convinced a majority to fallow them or fight with them. They hold the populace hostage and terrorize them as much as anyone else externally. So bombing indiscriminately (nuclear war is the ultimate carpet-bombing) would accomplish nothing.