The atomic bombs weren't close enough to vaporize anyone since they were detonated in the air, what you see is disintegration which is a little bit different and instead of turning the human body into what could be considered "nothing" the materials are torn apart and get embedded into the surrounding environment. Some vaporization did occur, but only on plants and the skin tissue of humans.
> instead of turning the human body into what could be considered "nothing"
You can't turn material into "nothing". At best you can turn it into equivalent amount of energy if you collide it with antimatter.
That being said I don't really feel the difference between "vaporisation" and "disintegration". In both cases you stop being biology and start being physics in a subjective instant. (at least from the perspective of your own central nervous system, which has not enough time to even detect that something has happened)
In both cases you go from a living, breathing, laughing, thinking human being into contaminants in the air or surfaces around you.
What do you feel is the difference between "vaporisation" and "disintegration"? Is it about how big your largest continuous chunk is? Where do you draw the line?