- 2001 Second-Team Academic All-Big 12
- 2001 Finalist for Nebraska Lifter of the Year Award
- Two-Time Big 12 Commissioner's Spring Academic Honor Roll (1999, 2001)
Casey Nelson earned a Blackshirt in 2001, which demonstrated his importance to the Husker defense as a senior. Nelson played in every game, including the Rose Bowl, alternating with Jeremy Schlecta at defensive tackle. Nelson was a finalist for the 2001 Nebraska Lifter of the Year Award after scoring the team's second-best Performance Index for defensive lineman with 2,281 points at the end of winter conditioning, an improvement of 209 points from his previous test. Nelson also posted a position-record 1.70 second 10-yard dash time. A solid student, he earned second-team academic All-Big 12 honors as a senior and was named to the Big 12 Commissioner's Spring Honor Roll on two occasions. He graduated in August 2002.
In 2001, Nelson totaled 31 tackles, which tied for ninth best on the team. He had six tackles for 20 yards lost, 1.5 sacks for 10 yards lost and two quarterback hurries. Nelson had five tackles in the season opener vs. TCU, four at Baylor, and closed the season with a career-best seven tackles at Colorado, including a career-high five solo stops. He did not have any statistics in the 2002 Rose Bowl.
Nelson served a valuable reserve role on the Husker defense in 2000, playing in 10 of 11 regular-season games (all except Colorado) as a backup defensive tackle to starter Loran Kaiser and Schlecta. Nelson had five tackles, including two solo stops and three quarterback hurries (one each vs. Notre Dame, Texas Tech and Kansas). Nelson had a season-best two tackles in each of NU's first two games, vs. San Jose State and Notre Dame. Nelson recorded one tackle and one quarterback hurry in the 2000 Alamo Bowl.
In 1999, Nelson played in three games and had two assisted tackles vs. California. Nelson did not see action in 1998, after redshirting as a walk-on in 1997.