They didn't blow it up with nano-explosives, not even sure if that is a word
They used nano-technology to interact with the particles from the explosion.
The guy is basically saying, you can see the particles with your eyes, so much of it - it makes you question things. Before they even got to the micro level, they could see the material was layered together - in the exact order it takes to create this super high heat explosives.
When you get down to the nano level, they separated out the trash and could see the atoms in the un-exploded particles are still in line, the elements are still pure, the layers of compounds are perfectly inline.
IE: Created and Placed by a Human, at a very very large scale.
As for a conspiracy theory... The United States on Record - Has attacked itself to start a war, has allowed itself to be attacked and has declassified documents that shows they had plans to attack our own people/soil to start other possible wars.
Stop being a damn sheep.....