Nix was introduced at a news conference yesterday as the Bills (5-10) prepare to close their season by hosting Indianapolis on Sunday. Nix fills a void after Marv Levy stepped down as GM following the 2007 season.

Chief operating officer Russ Brandon, who had been filling the GM’s role, was promoted to chief executive officer.

In introducing Nix, Wilson said it was important to him to hire someone with an extensive football background. That’s a switch from Brandon, whose background is in marketing.

“I’m here to introduce somebody that we’ve needed for a long time, something the fans and everybody in the area and myself have wanted, and that’s a general manager of football,’’ Wilson said, adding that his decision came down to two in-house candidates. “We really needed somebody who knew all aspects of football.’’

Wilson didn’t say who the other person was he considered.

At 70, Nix had been out of football after retiring in 2008 following a five-year stint as the 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.

“It’s not what I had in mind when I came back here in February,’’ Nix said. “The longer I’ve had time to think about it, the more excited I am about it . . . I believe very strongly that we can get this done. And I’m totally committed to do it.’’