We report the application of nanosecond transient grating spectroscopy to probe the excited state level structure of NO2 near 487.9 nm. Intensity and polarization grating transients were obtained in one-color (DFWM) and two-color (TC-RFWM) configurations. Most grating transients exhibit pronounced beats, arising from coherences among excited state hyperfine levels, which are enhanced in polarization grating experiments. Analysis of these beats yields detailed information on the excited state hyperfine level structure at a resolution 100 times smaller than the bandwidth of the applied laser fields. The grating transients are compared to predictions of the grating decomposition method (GDM) using Fourier transform analysis.