We present a new measurement of the gas-phase mass-metallicity relation (MZR) and its dependence on star formation rates (SFRs) at 1.3<z<2.3. Our sample comprises 1056 galaxies with a mean redshift of z=1.9, identified from the Hubble Space Telescope Wide Field Camera 3 (WFC3) grism spectroscopy in the Cosmic Assembly Near-infrared Deep Extragalactic Survey and the WFC3 Infrared Spectroscopic Parallel Survey. This sample is four times larger than previous metallicity surveys at z~2 and reaches an order of magnitude lower in stellar mass (10^8^M_{sun}_). Using stacked spectra, we find that the MZR evolves by 0.3dex relative to z~0.1. Additionally, we identify a subset of 49 galaxies with high signal-to-noise (S/N) spectra and redshifts between 1.3<z10)