For the 2004 season, Nemechek returned to MB2 Motorsports, taking over the No. 01 U.S. Army-sponsored car. He was again replacing Jerry Nadeau as the driver, although this time it was due to Nadeau suffering a severe injury that would eventually end his racing career. He won two poles late in the season. In October, Nemechek won at Kansas Speedway, beating out Ricky Rudd at the finish line. Nemechek also won the Busch Series race at Kansas the day before, making him the first driver to pull the Busch-Cup double win at the track.