CoCrFeNi high-entropy alloys (HEAs) face limitations in extreme environments due to inadequate hardness and wear resistance from their single-phase FCC structure. Herein, nano-TiC reinforced CoCrFeNi- xTiC composites (x = 0-5   wt%) were fabricated via selective laser melting (SLM), and the role of TiC in microstructure and high-temperature tribological behavior was elucidated. Tribological tests demonstrated that the composite with 4   wt% TiC exhibited optimal wear resistance, showing a 26.7% reduction in the coefficient of friction and an 89.8% decrease in wear rate at 600°C compared to the matrix alloy. TiC addition transformed the microstructure from a single FCC phase to an FCC matrix with dispersed nano-TiC, while synergistic grain refinement, solid solution strengthening, and second-phase effects increased Vickers hardness by 71.4%. Furthermore, high-temperature wear induced in situ formation of dense TiO₂ films, effectively reducing oxidation and wear. This work proposes a new strategy for designing tribologically robust CoCrFeNi-based HEAs.