"Nitro" fuel is a mixture of methanol, nitromethane and castor or synthetic oils. They will not run on gasoline or diesel fuel. Methanol is required for the engines to run, because it causes a catalytic reaction with platinum in the glow plug to ignite the fuel.

You can mix your own fuel, if you're willing purchase the ingredients and do the math on how much of each to mix up. IMO it's really on worth it if you go through a lot of fuel.