Justin--
Did you get this issue worked out?
I've had various wrestling matches with NITF images in ArcMap (various versions).
if you didn't find a solution, I wonder if under Customize-->ArcMap Options-->Raster-->Raster Layer, the box is checked next to Display Background Value. And if so it may be that it's checked to show band value 0 or 256 as white and/or "Display NoData as White"
I'd be interested to know how you solved this issue.
Luke