Microwave casting is an innovative method for melting and processing metallic materials using microwave energy. This novel technique offers green and faster processing with greater energy efficiency and less setup requirement compared to traditional methods. This approach can cast various cross-sectional shapes, including I, L, and T sections. I-shaped cross-section is a specifically designed cross-sectional shape with high specific strength. That is why it is widely used in numerous engineering applications such as for fabricating aircraft wings, fuselage structures, and automotive frames. Nickel-based alloys and metal matrix composites (MMCs) are preferred for aircraft and automotive components because of their strength, corrosion resistance, and ability to withstand in extreme temperature environments. In this work, a simulation study is conducted to analyze the casting of nickel powder into an I-shaped cross-section using microwave radiation at 2.45 GHz. The simulation employed the COMSOL Multiphysics tool to develop a 3D Finite element (FE) model of the microwave-assisted casting setup. In this study, the impacts of different microwave power levels (700, 900, and 1400 W) are investigated on microwave hybrid heating (MHH) during the casting process. Comparative analysis at different applicator power levels demonstrated that higher power levels enable uniform and rapid heating of the I-section nickel cast, regardless of its complexity.