The Denver Broncos head coach is still learning on the job, it would seem. An NFL head coach must always analyze things from a broad perspective. Taking stock of all the moving parts and making the correct split-second decisions requires a unique skill set — and it borders on a sporting art form if mastered. Denver Broncos head coach Nathaniel Hackett is learning the hard way that the same rules that applied as an offensive coordinator aren’t immediately interchangeable in his new role. The Broncos’ Week 3 tilt with the San Francisco 49ers will require Hackett to make complete a…