We present a module built into the PypeIt Python package to reduce high resolution Y, J, H, K, and L band spectra from the W. M. Keck Observatory NIRSPEC spectrograph. This data reduction pipeline is capable of spectral extraction, wavelength calibration, and telluric correction of data taken before and after the 2018 detector upgrade, all in a single package. The procedure for reducing data is thoroughly documented in an expansive tutorial.