Nix attended Midland High School in Midland, Texas, where he played both football and baseball. In addition to starting at quarterback for the football team, Nix was named to the All-Permian Basin Baseball Team before graduating in 2000. Nix was selected in the fourth round of the 2000 Major League Baseball Draft by the Texas Rangers. He made his debut on July 10, 2003, in a game against the Minnesota Twins. In that game, he recorded his first major league hit, and also scored a run. In December 2008, Nix signed a minor league contract with the Cincinnati Reds.