In recent decades, ensuring efficient thermal control of electronic components (ECs) has emerged as a critical concern. To address this, phase change materials (PCMs) are increasingly utilized to augment passive thermal management efficiency. In this work, a two-dimensional numerical study is conducted to investigate the melting of the PCM (n-eicosane) composited with metal foam (MF) and/or nanoparticles (NePCM) in a rectangular heat sink. The volume averaging technique based on the thermal equilibrium model is formulated for transient simulations. The impact of various parameters such as MF type, pores per inch (PPI), porosity, concentration of nanoparticles, and combination of NePCM and MF is investigated. Results show that the PCM/Copper foam composite with high porosity (0.95) and low PPI (10PPI) based heat sink provided a high rate of heat transfer and a more uniform melting process, which results in a drop in the electronic component temperature by 20.44 °C, and shortens the melting time by 648 s as compared to the pure PCM-based heat sink. In addition, the maximum effective thermal conductivity improvement of PCM is found to be 98% for Copper foam, with an effective latent heat reduction of 92.46%. Furthermore, outcomes reveal that using MF alone could notably enhance the melting performance. However, the addition of nanoparticles to cases involving MF, regardless of the nanoparticle volume fraction, adversely affects the melting performance of PCM. This indicates the negligible effect of nanoparticle insertion in the presence of MF. Therefore, in the context of this research, the cooling of the electronic component is primarily influenced by heat transfer through conduction than natural convection.