4C3H5N3O9 ---> 6N2 + 12CO + 10H2 + 7O2
You obviously didn't search very hard, because there are so many sources of info on NG in the Internet alone.
Ok, I'm sorry, I shouldn't try to act all high and mighty. Do you know the structure of NG? It's actually a misnomer, it really should be glycerin trinitrate.
Decomposition usually goes something like this...
C3H5N3O9 --> 3CO2 + 2.5H2O + 1.5N2 + 0.5O2