The synthesis of metal nanoparticles (NPs) in ionic liquids (ILs) solvent has been adopted as a greener alternative to conventional organic solvent reaction media, due to their environmentally benign and tunable physicochemical properties benefits. This study aimed to synthesize and characterize nickel nanoparticles (NiNPs) using imidazolium-based ionic liquids (1-ethyl-3-methylimidazolium methanesulfonate ([EMIM]MS) and 1-butyl-3-methylimidazolium methanesulfonate ([BMIM]MS) as both solvent and stabilizing agents, via a chemical reduction pathway. The NiNPs were characterized by UV-Visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy. The UV-Vis analysis showed broad surface plasmon resonance bands between 300 and 350 nm, confirming NiNP formation, with spectral shifts revealing smaller particles in [EMIM]MS compared to [BMIM]MS. FTIR spectra revealed characteristic bands for O–H, C–H, C–C, and C–N vibrations, indicating strong coordination between ionic liquid molecules and the nickel surface. SEM micrographs showed that NiNPs synthesized in [EMIM]MS were smaller (45–60 nm), spherical, and uniformly dispersed, and those obtained in [BMIM]MS were larger (60–80 nm) with slight aggregation. Synthesis was also done in ethylene glycol and the resulting NPs were irregular and aggregated. These results confirm that imidazolium-based ILs enable controlled synthesis and stabilization of nickel nanoparticles, providing a green and efficient route for nanomaterial production.