The success of next-generation chemical monitoring and molecular identification technologies hinges on the ability to resolve between different chemical environments. Fully-integrated evanescent Raman spectrometers can provide this solution; however, current materials used in excitation and collection optics are limited to near-infrared wavelengths, which have reduced Raman cross-sections when compared to visible wavelengths, and are not compatible with visible lasers and detectors. Here, we show that titanium dioxide (TiO₂) can serve a new material platform for evanescent Raman spectroscopy that can address these challenges. We experimentally show that visible TiO₂ nanophotonics increases the internal efficiency of the Raman scattering by more than two orders of magnitude over previous reports. Our TiO₂ nanophotonics demonstrate a material solution to the chemical sensing challenge and an opportunity to enhance future sensing functionalities of nanophotonics by innovating at the material level.