The application note details the optical characterization of plasmonic titanium nitride (TiN) nanohole arrays (NHAs) using angle-dependent reflectance spectroscopy. These NHAs, with varying TiN layer thicknesses (50 nm, 100 nm, and 150 nm), were fabricated to support plasmonic excitations for refractive index (RI) sensing applications. By employing the PerkinElmer LAMBDA 1050+ UV/Vis/NIR spectrometer with the TAMS module, the study measured the reflectance spectra at different incident light angles. The results demonstrated that the optical properties, including extraordinary optical transmission (EOT) and Fano resonances, are significantly influenced by the angle of incidence and the thickness of the TiN layers. The study's findings contribute to the optimization of plasmonic TiN nanostructures for compact, CMOS-compatible RI sensors.