Jordan Cyphers added 10 points for Tennessee State (12-7, 6-0), which has won eight straight at home.
M.J. Rhett finished with nine points and 10 boards for the Tigers, who outrebounded Jacksonville State 30-22.
Trailing at halftime 33-22, Jacksonville State shot 65.2 percent (15 for 23) in the second half and got within one possession in the final minute. Deshawn Dockery's 3-pointer with 13 seconds left, and 1 of 2 free throws by Miller, sealed the victory for the Tigers.
Tennessee State shot 50 percent (22 of 44) for the game and 57.1 percent (8 of 14) from downtown.
Ronnie Boggs scored 17 points for the Gamecocks (12-6, 4-3), who have yet to beat Tennessee State since joining the OVC in 2003-2004.