Even under high-pressure conditions, an oxide layer forms on the surface of metallic objects in an oxygen-rich environment. On the one hand, oxygen is frequently a substantial disruptor in many manufacturing engineering processes, and efforts have been undertaken to remove these oxide layers during manufacture. Oxide coatings on tools and workpieces, on the other hand, alter the wear mechanisms in various tribological systems, such as scratching and indentation, and can protect against corrosion. The mechanical properties of oxide layers and their link to the source material, on the other hand, are not entirely known. In this research, we examine the nanoindentation process on Al surfaces covered with a native oxide layer of varying thicknesses using molecular dynamics models and measurements. To describe the interaction between Al and O elements in the MD simulations, two interatomic potentials, COMB3 and ReaxFF, have been used. Our findings reveal that the oxide layer has a significant impact on fault emission in the substrate. The ReaxFF potential exhibits atom pile-up around the indenter, with no cracks found during the modeling procedure. In concordance with the results, we see crack initiation and propagation in the oxide thin film for the COMB3 potential. We detect a progressive trend of hardness for coated samples in both tests and simulations, which is related to the breakage of ordered ionic interactions.