In the paper, we numerically explored the combined impacts of non-linear thermal and mixed convective unsteady flow in a channel with slip conditions. The flow is caused by a moving flat parallel surface and is also electrically conductive. We analyse the mechanisms of heat, and mass transfer by incorporating temperature and concentration jumps. To simplify the model problem, we apply appropriate similarity transformations, reducing the prevailing problem to a nonlinear coupled ordinary boundary value problem. The transformed problem is solved using the Chebyshev Collocation Approach (CCA). We performed a comparative analysis by comparing the CCA with the literature to verify the accuracy of our approach, and a good agreement is found. In addition, we conducted a comprehensive parametric study to analyze the trends in the solutions obtained. The study reveals that the parameters M, α1, α3, Pr, and Sc have about 20% stronger impact on the nonlinear system compared to the linear system on both surfaces of the horizontal channel.