I always wear black nylons with a black dress in the evenings..
Absolutely you can. Perhaps go for an "off black" or "sheer black" color in the nylons. Pair that with pretty pumps or strappy sandals...
Wearing black covers up your body. You see it quite often when a person is not as slim as he/she wants, they wear black to hide the shape of their body. If you are confident with your body I would...