Javis Howard scored 15 points and grabbed 10 rebounds for the Buccaneers (5-2), who outrebounded the Rams 47-32 while making 12 of 26 3-pointers.
Both Harper and Nimely have surpassed 1,300 career points. Harper is ninth on the Charleston Southern career scoring list with 1,316 points, while Nimley is 10th with 1,314 points.
Marcus Praylow led Columbia International (1-9), an NAIA member, with 11 points.
The Buccaneers opened with a 20-9 run capped by two free throws by Cedrick Bowen. Nimley made three 3-pointers in a row and Charleston Southern led 49-27 and pulled away to a 55-32 halftime lead. Nimley scored 19 points in the half and Harper 14.
Charleston Southern opened the second half with a 12-2 run and continued to pull away.