Mohammed Faye finished with 15 points and eight rebounds, and Mike Walker had 12 points for the Mustangs (3-3).
Nyakundi had 17 points in the first half, and SMU led 52-41 at the break. The Mustangs' point total was their highest since a 99-96 double-overtime victory over UTEP on March 1, 2008. Their first-half total was their highest since scoring 55 against Louisiana-Monroe on November 11, 2006.
SMU never trailed and led by as many as 21.
Texas State opened the second half on a 9-0 run to pull to within 52-20 but never got any closer.