Nene Sound is a twenty-second audio clip in the game client that is not background music at all. It is a Korean advertising jingle for Nene Chicken, a South Korean fried chicken franchise, built around a single sung line that repeats four times before the brand name is delivered at the end.
It sits alongside the ordinary background music in the client, but no map plays it and nothing in the game refers to it. A restaurant chain's advertising jingle shipping inside a MapleStory client is an unusual thing to find, and it is the only piece of audio here that has nothing to do with the game.
No maps currently use this track. See Music for every track.