In supersonic expansion flows of humid nitrogen, at relatively low cooling rates, self-sustained oscillations may occur due to the combined effects of nucleation, droplet growth, and latent heat release. Different modes of oscillation are found depending on the initial humidity. It is shown numerically that the stability limit and the oscillation frequencies of the different modes strongly depend on the nucleation rate. Numerical results are compared with experiments of Adam and Schnerr and own experiments for nozzles of different shapes. The ICCT nucleation model yields correct results for both series of experiments, when corrected with a factor of the order of 0.01.