TiAlSiN nanocomposite coatings were deposited using deep oscillation magnetron sputtering with various nitrogen flow ratio (fN2) of 0%–20%. The increase of fN2 promotes phase separation from a single crystallographic TiAlSi to nc-(Ti,Al)N/a-Si3N4 phase. The introduce of N content leads to the formation of refined grain size, smooth morphologies and dense microstructure. Ti0.15Al0.39Si0.07N0.39 coatings with (Al + Si)/Ti ratio of 2.9 deposited at fN2 = 10% reach the highest hardness of 32.8 GPa, H/E* of and 0.0837 and H3/E*2 of 0.23. The introduce of N leads to failure mode changing from brittle tensile cracking (through-thickness cracking) to buckle spallation (interfacial failure). Ti0.15Al0.39Si0.07N0.39 coatings with highest H, H/E* and H3/E*2 ratios show buckling failure with high LC1 of 25.4 N and LC3 of 43.6 N. Correspondingly, Ti0.15Al0.39Si0.07N0.39 coatings are subjected to oxidation wear with low coefficient of friction of 0.41 and specific wear rate of 0.39 × 10−6 mm3 N−1 m−1.