It's used just as you have it.
A person with this kind of nerve (lack of fear) does not observe the formalities of etiquette. He speaks his mind regardless of whom he affronts or offends or insults.
Use the expression after someone commits a blatent act of selfishness, or criticizes someone for doing something improper, which he himself has often done.
Geez, I can't think of a good example. When a platter is first passed around at the dinner table, and the second person takes all the meat for himself, leaving nothing for the others, that would be "nerve."
Re the examples in Ray's site, many give the person credit for bravery. I think in the usage you quote, the expression is always used as a pejorative. (Well, almost always. You could admire someone's bravery while thinking he's crazy or stupid to risk his life on a useless stunt.)
Hmm, I see Ray spelled "effront" correctly and I didn't! 