I think Ucla wins by a solid margin. BYU is a good team, but you can run on high octane for only so long, and it will probably end against the Bruins. 35-17 type of win for Ucla.
The luck of the Cougars will run out. I must force myself to be a BYU fan the rest of the season (for the sake of the Huskers), but this game will be UCLA by 17-21 points.