Hydrogen production from overall water splitting assisted by organic oxidation reforming reaction is an innovative method to improve the anode behavior. Utilizing transition metal chalcogenides where the electronic states are regulated by anion modification, hexagonal Se‐NiSx pine‐needle‐like nanowires are prepared via a simple one‐pot hydrothermal reaction without any post‐processing steps. The nanowires can serve as ethanol electrooxidation reaction (EOR) catalyst with outstanding electrocatalytic activity (j100 = 1.36 V) and long‐term durability. In the practical tests of the hybrid water splitting, the catalyst required only 1.50 V to obtain 50 mA cm−2, and worked stably for over 50 h at a high current density of 200 mA cm−2 accompanied by an excellent selectivity (FE = 98.0%). These demonstrate that the introduction of Se significantly improves the catalytic performance of transition‐metal chalcogenides for EOR, indicating a new avenue for the design and improvement of other electrocatalysts.