The victory gave the Western Athletic Conference regular-season champions (20-10, 12-1) a 20-win season for the 26th time, and the fourth in a row and sixth in the last eight seasons under coach Marvin Menzies.
Nephawe collected his fourth double-double of the season and tied for seventh on the Aggies' all-time career rebounding list with Hamidu Rahman (2008-12) with 737.
Everett Osborne led the Broncs (9-20, 3-10) with 13 points. UTPA failed to score over the final 5:14 with New Mexico State finishing on a 10-0 run.
The game was originally scheduled to be played last Saturday but was postponed when the Aggies couldn't make it to Edinburg after their flight was canceled because of poor weather.