Nonlinear optical effects including stimulated Brillouin scattering (SBS) and four-wave mixing (FWM) play an important role in microwave photonics, optical frequency combs, and quantum photonics. Harnessing SBS and FWM in a low-loss and versatile integrated platform would open the path to build large-scale Brillouin/Kerr-based photonic integrated circuits. In this letter, we investigate the Brillouin and Kerr properties of a low-index (n = 1.513 @ 1550 nm) silicon oxynitride (SiON) platform. We observed, for the first time, backward Brillouin scattering in SiON waveguides with a Brillouin gain coefficient of 0.3 m−1 W−1, which can potentially be increased to 0.95 m−1 W−1 by just tailoring the waveguide cross section. We also performed FWM experiments in SiON rings and obtained the nonlinear parameter γ of 0.02 m−1 W−1. Our results point to a low-loss and low-index photonic integrated platform that is both Brillouin and Kerr active.