There isn't a huge amount to say about Nab Scar. Some would even argue that it isn't really a fell in its own right, but merely the bottom end of the Fairfield ridge. And while you're actually on the fell it doesn't feel like a separate entity at all. From the opposite side of the valley however, it looks altogether different and well worth the climb.
I dare say Nab Scar is usually climbed as the start of a Fairfield Horseshoe walk rather than a walk onto Nab Scar for its own sake. I can understand that if I'm honest because Nab Scar doesn't really cry out to be walked as a single fell.