Nolan previously served as a head coach for the San Francisco 49ers, and a defensive coordinator for the National Football League (NFL)'s Baltimore Ravens, New York Jets, Washington Redskins, New York Giants, Denver Broncos, Miami Dolphins, Atlanta Falcons, and Dallas Cowboys.

In 2000, Nolan was hired by the New York Jets as their defensive coordinator under head coach Al Groh.

[6] Following his hiring by the 49ers, Nolan asked the NFL for permission to wear a suit and tie on the sidelines as a tribute to his father.

A day later, Jacksonville Jaguars head coach Jack Del Rio sported another Reebok suit on Monday Night Football.

After further lobbying by Nolan, the NFL and Reebok reached an agreement to allow suits to be worn at all home games in the 2007 season.

In early 2009, Nolan was hired by the Denver Broncos as the defensive coordinator under head coach, Josh McDaniels.

Nolan faced heavy restrictions due to the COVID-19 pandemic in terms of physical contact with the players, their availability due to a positive test for COVID-19 or having been exposed to someone who had it, a reduced training camp schedule and the cancellation of preseason games, which made it difficult to implement his defensive scheme.

[8] On February 3, 2023, it was announced that Nolan was hired by the Michigan Panthers of United States Football League (USFL) to be their head coach, succeeding Jeff Fisher.

Despite the mediocre record, the Panthers reached the playoffs, and faced the Pittsburgh Maulers in the USFL North Championship Game where they lost 31–27 in overtime.

Due to the Panthers surviving the USFL and XFL's merger into the UFL, Nolan kept his job as head coach.

[10] Unfortunately for Nolan, the Panthers lost to the Birmingham Stallions in the USFL Conference Championship Game 31–18 after leading 18–3 at halftime.

[12] Nolan attended Bellarmine College Preparatory in San Jose, California and Woodside High School, the alma mater of Julian Edelman.