A state-specific model is developed to analyze the complex chemistry-vibration coupling present in high enthalpy nozzle flows. A basic model is formulated assuming molecules are formed at a specific vibrational level and allowed to relax through a series of vibration-vibration and vibration-translation processes. This is carried out assuming that the molecules behave as either harmonic or anharmonic oscillators. The results are compared with the standard vibration-chemistry model for high enthalpy nozzle flows. Next, a prior recombination model that accounts for the rotational - vibrational coupling is used to obtain prior recombination distribution. A distribution of recombining states is obtained as a function of the total energy available to the system. The results of this model are compared with recent experiments.