On the first of Bo Nix’s four touchdown passes against Green Bay last Sunday, he did what he does more frequently than any quarterback in football.

Nix escaped from the pocket and took off running. He moved up and to the left before hitting Michael Bandy for a 20-yard catch-and-scamper.

The next three touchdowns, though, are where the Broncos’ offense can dream about a deep postseason run or even more.

Nix, operating from the gun, delivered strikes of all shapes and sizes and did so with clean footwork in the pocket.

He identified coverage, took a short, one-step drop and fired a perfectly placed low ball to Lil’Jordan Humphrey. Then, a three-step drop to get the ball up and down with beautiful pace and timing to Courtland Sutton one-on-one up the right sideline.

Nix polished off the fourth touchdown when he five-step dropped, hitched up in the pocket twice, and uncorked a rocket up the seam for Troy Franklin on a motion-and-route concept the Broncos have made hay on most of the year.

The Packers game represented a breakout as Nix completed 23 of 34 passes for 302 yards and those four touchdowns, but his game has been heating up more broadly over the past month.

He had an efficient day, albeit in a much different style against Las Vegas, completing 31 of 38 passes and engineering three battering-ram touchdown drives. He threw for 616 yards in the two weeks before that in wins over Washington and Kansas City.

In those four games, Nix has completed 69.5% of his passes for 282.5 yards per game and thrown five touchdowns and an interception. Before that stretch, he completed 60.9% and averaged 212 yards per game.

What’s changed? Start from the ground up.

“I think his footwork has got a lot better,” offensive coordinator Joe Lombardi said Thursday. “And the way he handles himself in the pocket, trusting the protection. We’ve talked about it all year and the last four games he’s done a really good job of that.

“He’s moving when he needs to and he’s hanging in there when he needs to.”

Head coach Sean Payton said earlier this season that the quarterbacks get some specific footwork drilling during a typical game week, but not a ton. They’ll work a particular concept or drop between periods, but for the most part, the work is plan-specific.

Nix, though, has been working on his own pocket presence in his own ways in recent weeks.

“I think he’s probably one of the best … at learning from mistakes, and looking in the mirror and seeing what his weaknesses are,” tight end Evan Engram told The Post.

“He’s sitting in there, he’s trusting the protection, he’s letting it rip. And that’s something that he saw. And he worked on. And like – I can’t say how hard that is. I’ve never done it in my life. You’ve got freakin’ monsters rushing you, every play. And credit to the O-line, too.”

The staff also appears to be doing a better job of helping Nix find his rhythm. Part of that comes from playing more frequently from under center. The touchdowns outlined above came from the shotgun, but one commonly held belief is that playing from under center helps keep footwork clean because a quarterback is forced to do so on the way back from the center.

Since the Broncos returned from their bye week, the uptick has been notable.

Denver averaged 29.4% of offensive snaps under center in the first 11 games. Over the past three games, the number is 42.8%.

Nix has attempted nearly half as many passes from under center the past three games (25) as he did in the first 11 (51). That’s partly because he’s playing more from under center, though Denver’s under-center pass rate has also increased from 24.5% over the first 11 games to 29.3% the past three weeks.

Nix only completed 1 of 6 passes against Green Bay for 16 yards from under center. However, the week before, he was 10 of 10 for 71 yards against Las Vegas.

“Each game is different relative to when we look at gun runs, under-center runs, try to self-scout ourselves enough to where there’s enough play-action, maybe under center, drop back,” Payton said between Vegas and Green Bay, adding that he thought Nix made a quick transition to playing under center even though he hardly did it in college at Oregon.

“I think that hasn’t been a big learning curve. I think it’s gone pretty smooth,” Payton added.

Particularly since the bye week, the Broncos have leaned more and more into it. Payton and Lombardi say usage depends on individual game plans.

The longer this uptick continues, though, the more it looks like a philosophical shift.

Broncos reporter Luca Evans contributed to this story. 

Want more Broncos news? Sign up for the Broncos Insider to get all our NFL analysis.