This recognition, which honors academic performance, community service, and athletic success, is memorialized in this article from SI. It discusses his involvement with some Durham-area schoolchildren, and how their performance has improved academically since Thornton entered their lives. It's worth noting that Thornton is a member of the NABC "Good Works" team.
Other nominees have more impressive stats--Trey Burke is the other college basketball player listed--but this is great recognition for a great student-athlete in Tyler Thornton. Kudos and keep it up.