If nose is straight after fracture-- but there is a bump - is closed nasal reduction w/general anesthesia necessary? (photo)

If there has been no change in the contour of the nose on frontal view (shift, crooked etc), a closed reduction is not indicated - at least in my opinion. A new or larger bump will likely not improve with the reduction. Wait for all the swelling to have subsided (3 to 6 months). At this point, the nose should be assessed and a possible rhinoplasty considered. 

As you noted, your nose looks straight to you.  There is no need for a closed reduction of your nose.  The nasal bump you have should be allowed to settle and fully soften, which takes 4-6 months and then reevaluated to see if the nasal contour has returned to its pre injury shape.  If it has, nothing further needs to be done.  If a bump remains, you may wish to improve that contour by a rhinoplasty.  Patiente is best for now.

 Trauma to the nose can create a displaced, or non--displaced nasal fracture. Only displaced nasal fractures need to be manipulated and straightened. In our practice, we prefer to perform an open reduction nasal fracture to realign the nasal bones straight. This is accomplished with a closed rhinoplasty approach with all incisions made on the inside of the nose. We rarely ever perform a closed reduction of a nasal fracture. The nasal hump can also be addressed at the same time by filing  it down. Best to wait a few months to see if it goes down on its own.  In our practice, all nasal surgery is performed under general anesthesia by a board-certified physician anesthesiologist in our Medicare certified outpatient surgery center for patient safety and comfort.