Ripley's Aquarium of the Smokies in Gatlinburgh, TN offer a nursing mothers room area located in the women's restroom. Amenities are simple but include two comfortable rocking chairs and changing tables.
A mom wrote in 2008: this attraction has a nursing room in the bathroom by the entrance. (The only bathroom I saw, not sure if there’s any others.) It was a very plain room inside the women’s bathroom, but there were 2 wooden rocking chairs, enough room for a few large strollers, and the door had a lock on it. There were changing stations outside of the room, in the bathroom, 2 of them, I believe. This nursing station was nothing special, by no means, but I was still grateful for it.
Update: Mom wrote in June 2012: "Its a beautiful aquarium. Lots to do for little ones. And they have a nice, clean nursing room for mothers. Has two rocking chairs and a changing table."