Martin Seiferth added 13 points, 10 rebounds and four blocks for the Eagles (8-17, 6-9 Big Sky), who shot 54 percent from the field.
Jackson Stevenett led Southern Utah (10-15, 8-8) with 26 points and eight rebounds. AJ Hess hit 5 of 10 3-point attempts and finished with 24 points. Those two combined to hit 12 of 25 shots from the field, while the rest of their Thunderbirds teammates shot 23 percent (9 for 39).
Chiverton hit a 3-pointer to start a 10-2 run and capped it with a jumper to give Eastern Washington a 28-18 lead with 5 minutes left in the first half. The Eagles led 39-31 at the break and equaled their largest lead of the game when Jeffrey Forbes scored to make it 58-41 with 12:53 remaining.