there are also certain bugs that can live without a head for some time (but then again they don´t really have a brain, and their body works on a different way)
This is Toriko tho, there are weirder things than a fictional creature being able to stroll about after losing its head.
Also, it was said the nitros that were sent to the festival were RED nitros, which are of a weaker kind.
@King Haki: We saw the first nitro on the ozone herb arc.