Using cascaded intensity and phase modulators to achieve frequency combs is a common technique. However, this technique has not yet been employed to achieve optical frequency combs (OFCs) at the nanoscale. A theoretical model based on temporal coupled mode theory is developed to simulate an all-optical photonic crystal modulator. The concepts used to generate an OFC based on electro-optic modulators are then extended to the nanophotonic domain. It is theoretically proven that an OFC can be generated via all optical modulation of nanophotonic devices.