NBC Nightly News may have Fallen To second place in the ratings and the network's magazine show, Dateline, may have been sidelined since the start of the season, but the two shows dominated the list of the Radio and Television News Directors Assn.'s Edward R. Murrow Award winners announced Sunday. NBC News also received the top award for overall excellence. Of the 13 prizes, NBC won seven, CBS three, CNN two, and ABC -- the ratings leader -- just one (for a feature report about a blind trumpeter, no less).