A chemical oxygen-iodine laser (COIL) with nitrogen buffer gases was designed and experimentally investigated. An output power of 2.6 kW was obtained for a chlorine flowrate of 140 mmol/s, corresponding to a chemical efficiency of 20.4% and a nozzle power flux of 74 W/cm². The results approach the performance of the similar scale COIL with helium buffer gases in previous research.