In previous works it has been shown that the glass forming ability of metallic alloys can be modified by the addition of nanoparticles that perturb the alloy crystallization. In this work previous results are compared with results from new samples produced with a higher cooling rate. The results are interpreted in terms of a Kinetic model that predicts that nanoparticles modify the nucleation rate with a very sensitive dependence on the particle volume fraction and size. It is shown that the effect of the particles is to change the critical cooling rate by about one order of magnitude and that the particle concentration must be adjusted within a narrow range.