We performed a study on the effects of a given bath gas and the angle of deposition on the conformer abundance of CH3ONO during deposition in a low-temperature matrix using three different inert bath gases: nitrogen (N2), argon (Ar), and xenon (Xe). Our observations indicate a change in conformer abundance that occurs between the gas and matrix phases. Changes to deposition angle were additionally found to alter conformer abundances in a N2 bath gas, while conformer abundances in Ar showed no angular dependence. We investigate the competition between effects of surface morphology and energetic stabilization on the trapping of the two conformers by analyzing the angular dependence of the abundances and performing quantum chemistry calculations of the gas:CH3ONO complexes. We propose that the surface formation dynamics of N2 change with the angle of deposition, affecting the conformer abundance. Quantum chemistry calculations of N2:CH3ONO also indicate that cis-CH3ONO is energetically stabilized relative to trans-CH3ONO. Quantum chemistry calculations of X:CH3ONO (X = Ar, Xe) do not indicate significant stabilization of either conformer. We thus attribute the increase in cis-CH3ONO abundance in Ar and Xe matrices to its smaller van der Waals radius, enhancing the probability of trapping within pockets during surface diffusion. These size effects are also likely to contribute to the enhancement of cis-CH3ONO in N2.