The reactivity-promoting effect of trace nitrogen oxides (NOx) on post-induction oxidation of a synthetic natural gas (2% ethane in methane) has been experimentally studied in a high-pressure laminar flow reactor (HPLFR) at 10 +/- 0.1 atm, nominal reaction temperature of 818 +/- 5 K, and several equivalence ratios (phi similar to 0.5, 1.0, and 2.0). Each set of experimental measurements was simulated using several literature C-0-C-2 + NOx kinetic models, both recent and legacy, using approaches shown to lead to robust interpretation of present experimental conditions. Coupling between the NOx and C-0-C-2, submodel components of these models varies significantly in both qualitative (mechanistic) and quantitative character. A comparison among the experimental measurements and modeling results serves to highlight important kinetic features particular to application-relevant natural gas oxidation in presence of trace (similar to 25 ppm) NOx. Additional insight is offered by a baseline experiment with no NOx perturbation, which shows that synthetic natural gas exhibits only incipient reactivity under the present phi similar to 1.0 experimental condition. A comparison across experimental measurements and simulation results suggests that the reaction CH3 + NO2 <-> CH3O + NO, often cited as among the most important for NOx-natural gas coupling, insufficiently describes the principal net flux of NOx species at the relatively high pressures and low temperatures examined by present experiments. Simulation results indicate that accurate kinetics related to CH3O2 are necessary to describe a portion of NO <-> NO2 cycling driven by fuel fragment chemistry. Modeling suggests that the formation of nitromethane (CH3NO2) from the relatively large and long-lived CH3 pool removes NOx from the pool of reactive intermediates, thus altering the reactivity initially imparted by trace NOx addition and the total pool of N atoms available as free NOx (NO + NO2). Frequently used kinetic models that lack (accurate) CH3O2- and CH3NO2-related submodels predict trends in overall reactivity and NOx mole fractions that vary from quantitatively distorted to qualitatively incorrect. These disparities have significant implications for combustor design/evaluation computations that rely on several present literature kinetic models, particularly in a "single digit" parts per million of NOx regulatory environment.