This two-dimensional numerical study explores the thermal performance of a hybrid nanocomposite phase change material (HNCPCM) dispersed metal-foam with open slots embedded heat sink for passive cooling enhancement of electronics. The hybrid nanoparticles of GO-Ag of varying volume fractions from 0% to 6% are dispersed into the RT-28HC, used as a phase change material (PCM). The metal-foam strips of constant width and height are embedded inside the heat sink to improve the heat transfer rate and melting process of PCM at a constant power level. Unsteady simulations are conducted to solve the governing equations numerically using the Finite Volume Method (FVM) scheme. The results depicted that employing HNCPCM has better heat transfer enhancement compared to the pure PCM because of the addition of nanoparticles. The 2% volume fraction of GO-Ag showed the higher melting time and optimum heat transfer rate. The composite of HNCPCM/metal-foam strips showed better uniformity in the melting of PCM and lower heat sink temperature is achieved which results in better passive cooling performance for electronic devices.