We present a new detailed non-LTE model of OH and CO₂ emissions in the nighttime mesosphere/lower thermosphere (MLT). The model accounts for chemical production of vibrationally excited OH and for various vibrational-vibrational (VV) and vibrational-translational (VT) energy exchanges with main atmospheric constituents. It also accounts for the new "indirect" vibrational-electronic (VE) mechanism OH(v) → O(¹D) → N₂(v) → CO₂(v₃) of the OH vibrational energy transfer to N₂ and further to CO₂ vibrations, which was recently suggested by Sharma et al. [2015] and proved in laboratory studies by Kalogerakis et al. [2016]. We study the impact of this mechanism on the OH(v) and CO2(v) populations and emissions in the SABER/TIMED channels at 1.6, 2.0, and 4.3 µm, as well as compare our modeled results with ground and space observations of OH(v) densities. We show that our model reproduces these ground and space observations for various atmospheric conditions significantly better when compared to previous studies. First results of this model application to the self-consistent three-channel OH, O(³P) and CO₂ retrievals from SABER nighttime observations of the MLT will be discussed.