We developed a wavelength-tunable second harmonic scattering experimental setup to investigate dispersion of the nonlinear optical response of three different nanocrystal suspensions (LiNbO_3, ZnO and BiFeO_3). Special attention was paid to reproducibility issues with the implementation of a detailed protocol that allows correcting for the setup spectral response. The absolute, orientation-averaged second order susceptibilities of the three nanomaterials were then assessed in the 700-1300?nm spectral range evidencing very specific optical signatures. The well-defined resonances observed for ZnO and BiFeO_3 near their electronic transitions were found to be poorly described by the Miller’s rule.