Kyle Boswell added 12 points and Jaime Serna 10 for the Gauchos (2-0). Nunnally added a game-high eight rebounds, and Nate Garth had five assists.
Niyi Harrison scored 15 points to pace the Broncos (1-1). Kevin Foster added 12.
The game turned midway through the first half. After Santa Clara went ahead 17-14, UC Santa Barbara launched an 18-0 run to grab a 32-17. The Broncos scored only one basket in the final 10:58 of the half and trailed 42-24 at intermission.
Santa Clara was limited to 32.8 percent accuracy (20 of 61) and shot just 18.2 percent (4 of 22) from 3-point range. The Gauchos shot 47.5 percent (29 of 61), made 6 of 20 3-pointers and held a 47-31 rebounding advantage.