Dekker went 4-for-5 from 3-point range and Ben Brust chipped in 13 points to give the Badgers (20-8, 11-4 Big Ten) their sixth victory in seven games, and their third conference win by 20 points or more.
The Badgers led 44-23 at halftime and started the second period with an 18-3 run.
Wisconsin led nearly the entire game and shot 50.9 percent from the field to 32.8 percent for Nebraska (13-15, 4-11). Wisconsin also won the battle of the boards 37-29.
Dylan Talley led the Cornhuskers with 21 points and eight rebounds. Brandon Ubel finished with 10 points and six boards.