For one snap Sunday, the Broncos offense peered over the edge and into the abyss. This wasn’t a big mistake, fiery exchange on the sideline or loose ball bouncing on the Empower Field grass. This was a stress test on the engine that makes any offense go and is of particular importance to Denver’s operation this fall with a rookie quarterback: The offensive line. That rookie quarterback, Bo Nix, snapped the ball once Sunday against Las Vegas with a No.