SIOUX FALLS, S.D. & BUTTE, Mont.–(BUSINESS WIRE)–NorthWestern Corporation, a regulated energy service company operating in Montana and a subsidiary of NorthWestern Energy Group, Inc., doing business as NorthWestern Energy (Nasdaq: NWE), filed an application with the Montana Public Service Commission requesting approval of a Large New Load Tariff rule to establish requirements and contract terms for providing electric service to bundled customers with new or expanded loads of 5 megawatts or gr