Howell was promoted to serve as BYU's defensive coordinator in March 2013. He also serves as the BYU secondary coach.

He helped a defensive unit at BYU finish the regular season ranked No. 6 nationaly in sacks per game and No. 15 in tackles for loss after the Cougars ranked No. 20 in rushing defense in 2014.

Despite having to defend more plays than all but four teams nationally in 2013 due to BYU's new uptempo offensive system, the Cougar defense ranked No. 12 nationally in yards-per-play defense, No. 16 in pass efficiency defense and No. 22 in scoring defense. Howell helped the BYU defense rank No. 3 in total defense (266.1 yards allowed) and pass defense rank No. 10 in passing yards allowed (179.2 ypg) in 2012.

In 2011, he helped the pass defense rank No. 15 in pass efficiency defense, allowing a rating of 112.58. In that same year, the Cougars ranked No. 13 in overall defense. 

He first came to BYU in 2007 as a defensive intern and then served two years as a graduate assistant before being hired as an assistant coach in 2010. Since first being hired by Bronco Mendenhall in 2007, he has helped coach defensive backs and linebackers. Howell started as a full-time coach working as the team’s outside linebackers coach before taking over the BYU secondary partway through the 2010 season.

Prior to coming to BYU, Howell was the head coach at Ben Lomond High School (Ogden, Utah) from 2004-2006 and served as defensive coordinator at Weber High School (North Ogden, Utah) in 2003 and defensive line coach at Sky View High School (Smithfield, Utah) in 2002.

A native of Ogden, Utah, Howell earned a M.A. in education with teaching certification from the University of Phoenix in 2007 after receiving his undergraduate degree in history from Weber State University (Ogden, Utah) in 2005. Howell and his wife Brooke have four children.

Howell's contributions at BYU have helped the Cougars put one of the nation's top defenses on the field each year. In 2013, Howell was a candidate for the Broyles Award, given annually to the nation's top assistant coach.

Bronco Mendenhall on Howell's hiring: “Nick is one of the brightest young football coaches in the country. He is extremely diligent, energetic, and hard working. He is passionate about BYU. I am thrilled to have him continue to be part of our staff, and I am confident he will be successful in building on what Coach Lamb has done here at BYU.”

Bronco Mendenhall on Howell's promotion to Defensive Coordinator: “Nick has already been serving in this capacity in many ways but without formal recognition of that role,” Mendenhall said. “Whenever I have been unable to stay with our defensive coaches due to my responsibilities as the head coach, Nick has provided that leadership in my absence. I will maintain play-calling duties and continue to work with Nick in our established pattern regarding the daily oversight of our defense.”