Sean Payton has a monumental task in preparing his team for Sunday’s wild-card game at Buffalo, so the second-year Denver Broncos coach isn’t wasting time relishing in proving his doubters wrong.The prospect of the Broncos ending a playoff drought that had dated back to their Super Bowl-winning season of 2015 appeared dim after Payton’s first year in Denver ended with an 8-9 record and a parting with quarterback Russell Wilson.But in stepped rookie Bo Nix, who threw a career-high-tying four touchdown passes in leading Denver to its 10th victory of the season on Sunday. In doing so, the Broncos clinched the No. 7 seed in the AFC playoffs and a date with the second-seeded Bills on Sunday.It has been a quick and dramatic turnaround for a franchise that was mired with massive salary cap restraints when Payton arrived just two years ago.”We all like a challenge, right? I guess it’s like a challenge when someone says ‘X.’ The first thing I think of is, ‘Who is that someone?'” Payton said Monday. “… I think your players certainly do have a little bit of a chip when they see those initial prognostications or whatever. Then eventually when you’re in this long enough, you tune that stuff out because half those people don’t have a clue what they’re talking about.”Yes, who’s done this before with over $80 million (in dead cap) — all those things you think about. No one’s done that before. Let’s be the first one.”Payton faces a different type of challenge in preparing his team for the Bills, who went 13-4 during the regular season and are led by quarterback Josh Allen, who many believe will win his first Most Valuable Player award.Buffalo went 8-0 at home during the regular season, and began the week as a consensus nine-point favorite.