I am not a scientist, or have any professional knowledge of bombs or explosives. What I say here is merely my opinion of what I saw in the videos. Take it for what it's worth. .....
I didn't see a "mushroom cloud" in the videos. What I saw was a very powerful explosion, which created a massive shock wave which in turn compressed the air so much that it literally squeezed the moisture out of the air. And that in turn "dissipated" almost immediately as the shock wave passed and the moisture was then re-absorbed back into the atmosphere. I didn't see any cloud of smoke. It was just water vapor.
You can find many pictures on the internet of military jets creating the same phenomenon. I say military jets because a jet has to be going pretty dang fast in order to do that, and usually that means a military jet. Anyway, my opinion is that there was no nuclear blast involved here.