In advancing hydrogen fuel production through water-splitting, we focus on the optimisation of 1T/2H phases of MoS2 nanoparticles to enrich the overall water-splitting performance which has garnered significant interest. We propose a straightforward hydrothermal method to develop a 1T/2H MoS2 catalyst by introducing Ni. Morphological and chemical investigations evidenced the generation of the metal/semiconductor MoS2 nanoparticles. Further, the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) have been demonstrated, and the optimised 1 m mol nickel-doped MoS2 catalyst (MSN-1) exhibits remarkable performance in both HER and OER, with a low overpotential of 117 and 250 mV respectively at a current density of 10 mA cm−2, and superior stability in alkaline medium (about 20 h). Additionally, it exhibits promising bifunctional activity with an overpotential of approximately 1.36 V at a current density of 10 mA cm−2, maintaining stability for 20 h in a 1.0 M KOH medium. These outcomes emphasise that MSN-1 has the potential as a practical bifunctional electrocatalyst with significant applications on the horizon.