Nogales Wastewater Improvement Act of 2023 This bill establishes requirements to address wastewater from the International Outfall Interceptor, which is a pipeline that carries wastewater from the United States-Mexico border to the Nogales International Wastewater Treatment Plant. The plant, which is located in Rio Rico, Arizona, treats sewage and wastewater originating from Nogales, Mexico, and Nogales, Arizona. The bill transfers the ownership, operations, and maintenance of the pipeline from the city of Nogales, Arizona, to the U.S. Section of the International Boundary and Water Commission. The commission must construct, operate, and maintain a debris screen at the pipeline's Manhole One for intercepting debris and drugs coming into the United States from Nogales, Mexico. The bill also limits the portion of the costs that the city of Nogales, Arizona, must pay for the Nogales sanitation project.