  The two-detector design of the NOvA neutrino oscillation experiment, in which
two functionally identical detectors are exposed to an intense neutrino beam,
aids in canceling leading order effects of cross-section uncertainties.
However, limited knowledge of neutrino interaction cross sections still gives
rise to some of the largest systematic uncertainties in current oscillation
measurements. We show contemporary models of neutrino interactions to be
discrepant with data from NOvA, consistent with discrepancies seen in other
experiments. Adjustments to neutrino interaction models in GENIE that improve
agreement with our data are presented. We also describe systematic
uncertainties on these models, including uncertainties on multi-nucleon
interactions from a newly developed procedure using NOvA near detector data.
