The increasing focus on rare-earth-based intermetallic materials has intensified the search for compounds capable of delivering superior performance in low-temperature magnetic refrigeration systems. In the present work, we theoretically examine the electronic, magnetic, and magnetocaloric characteristics of the NdSi intermetallic compound by employing a hybrid computational approach that combines density functional theory (DFT) and Monte Carlo simulations. DFT results indicate a magnetic moment of approximately 3.36 µB per Nd3+ ion. To further assess the magnetic response, Monte Carlo simulations were conducted using DFT-derived exchange coupling constants as input, enabling analysis of magnetic ordering, isothermal magnetic entropy variation, and relative cooling power (RCP) near the Curie temperature (Tc = 47 K). The computed peak value of the magnetic entropy change (ΔSm) is 12.1 J·kg−1·K−1, while the corresponding RCP reaches 201 J·kg−1 under an applied magnetic field change of Δh = 0–5 T. These outcomes underline the excellent magnetocaloric potential of NdSi, suggesting its viability as a high-efficiency, low-temperature refrigerant and a compelling substitute for other intermetallic systems in next-generation cooling technologies.