Peters added a game-high 11 rebounds and Nickerson finished with seven.
Valparaiso opened the game on an 8-2 run and led 31-21 at the break. A Matt Van Scyoc 3-pointer capped a 21-10 stretch to open the second half and the Sycamores (3-5) led 42-41 with 12:13 to go.
The Crusaders regained control by stringing together an 18-9 spurt, capped by a Skara 3-pointer, to give them a 59-51 lead which they did not relinquish.
Van Scyoc had 20 points for Indiana State. Brenton Scott finished with 16.