As an advanced surface modification technology, laser cladding technology can significantly improve the hardness, wear resistance, and corrosion resistance of the base material by forming a high-performance composite coating on the surface of the substrate. In this paper, In718 nickel-based high-temperature alloy was used as the substrate, and laser cladding technology was used to prepare In718/(2Nb + 1SiC) composite coatings, and the effects of different laser powers (800 W, 1200 W, 1600 W, and 2000 W) on the microstructure and wear-resistant properties of the coatings were systematically investigated. Through SEM morphology observation, EDS elemental distribution analysis, wear behavior characterization, wear mechanism discussion, the regulatory mechanism of laser power on the microstructure evolution, the uniformity of reinforced phase distribution, and the coating properties were revealed. The results show that different melting powers significantly affect the phase structure and the generation of reinforcing phases in the In718/(2Nb + 1SiC) composite coatings. A 1200 W laser input power can make the coatings reach the optimal phase structure equilibrium. Both properties of the SiC-reinforced phase are retained, and a large number of NbC- and MoC-reinforced phases are generated. This results in excellent properties for the coating.