Nix was introduced at a news conference Thursday as the Bills (5-10) prepare to close their season hosting Indianapolis (14-1) on Sunday. Nix fills a void after Marv Levy stepped down as general manager following the 2007 season.
Chief operating officer Russ Brandon, who had been filling the GM's role, was promoted to chief executive officer, reporting to Wilson.
At 70, Nix had been out of football after retiring in 2008 following a five-year stint as the San Diego Chargers assistant GM/director of player personnel.
He came out of retirement to return to Buffalo this past year after serving as the team's area scout from 1993-2000.
Nix has 14 years of NFL experience, mostly in scouting, and previously spent 26 years coaching in the college ranks. That included a nine-year term as head coach at Tennessee-Chattanooga, where he coached Bills receiver Terrell Owens during his freshman year.
He takes over what's been a dysfunctional franchise that will miss the playoffs for a 10th straight year, and closes this decade with one winning season — a 9-7 finish in 2004. Buffalo is also in the midst of its fourth coaching search since 2001 after Dick Jauron was fired in November and replaced by defensive coordinator Perry Fewell, who has a 2-4 record as interim head coach.
Nix's first task will be choosing a head coach. As a first-time head coach, Fewell is considered a candidate, but the Bills are expected to look for someone with previous experience. Two-time Super Bowl winner Mike Shanahan interviewed for the job, but has reportedly turned down the Bills.
With Nix in place, it's uncertain whether the Bills will retain chief scout Tom Modrak, pro personnel director John Guy or Jim Overdorf, the team's senior vice president of football operation.