No, nitrous is just compressed oxygen basically (with some nitrogen in it!) And it burns a lot more efficiently than normal air. But as it is only oxygen it still needs a propellant to make it burn! The point is that it has its own fuel injector that comes on with the nitrous, therefore no extra fuelling is required from the normal injectors.

Or if you are Sean Bicknell, you can go one step futher and map the nitrous fuelling into the normal injectors!