A groundburst nuke would have produced a blinding flash. No flash. There would also be all kinds of radiation signatures that any university-level physics department or nation in the region could detect.
Maybe the radiation readings are yet to come out or to be covered up but as to the the blinding flash, that is not a requirement or affect of every weapon system of the many different types (yes, there are) of smaller lower grade tactical nukes. The military’s of not just the United States but others have weapon systems that we are not privy to or have knowledge of. I still say it was a small military tactical nuke or a very crude, low yield nuclear bomb. 100 “mother of all bombs” could not have the same signature concussion or devastating effect that this incident shows.