Nash netted 24 points and Smart provided 21 for the Cowboys (23-7, 13-5 Big 12), who got back on the winning track following a Wednesday loss at Iowa State.
They clinched the third seed in next week's Big 12 conference tournament with the help of Markel Brown, who finished with 16 points.
Rodney McGruder scored 22 points and Thomas Gipson came off the bench to add 15 for the Wildcats (25-6, 14-4), who finished with a share of the Big 12 regular-season title despite the loss thanks to Baylor's defeat of Kansas later Saturday.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'