First off, they are NOT going to nuke it. Potentially converting a disastrous oil leak from a pipe into a radioactive crater leaking radioactive oil would most definitely not be an improvement. On land it might be an option but at a mile down and then having to be placed in drill hole, a hole we would have to create, with considerable precision it is just not going to happen.

Second, if this might be done it would be undertaken with conventional explosives. A lot of the research we have undertaken has been centered on how to substitute conventional explosives with precision targeting to accomplish strategic goals without the problems associated with nuclear weapons.

Over time nuclear weapons systems have drifted toward smaller yields delivered with precision instead of high yields delivers in the general vicinity. Like a shotgun high yields are used to compensate for weak targeting and scattered delivery. Point being that in a war if you can guarantee delivery to within a few feet a conventional warhead work as well as a nukes. And they are cheaper and easier to clean up afterward.

But here again blowing the well, using nuclear or conventional explosives, won't necessarily guarantee that the flow stops. You could shatter or split the casing hundreds of feet below ground and make the situation worse.

Third, there isn't going to be any significant evacuation. Nobody is sure exactly how toxic the oil is. It clearly isn't immediately toxic if you don't have any serious medical conditions. People with asthma and heart conditions may want to steer clear of the oil and any fumes but most of the short term effects seen seem to be from the smell and the heat. Evacuation of the population has not even been seriously considered.

People should deeply contemplate why they go to internet sites that promote these sorts of stories. Being spoon-fed fantasy worse-case scenarios doesn't help anyone prepare for anything.