According to "Williams, David, 1993, The Georgia Gold Rush: Twenty-Niners, Cherokees, and Gold Fever, Columbia: University of South Carolina Press". He was told about gold being there according to the book.
You might have to have De Soto not die and/or Luis de Moscoso Alvarado decide that a colony could be founded to change anything. De Soto can be pointed to as the reason the Native Americans in the present-day US had bad relations with Europeans.
To change anything you need De Soto to not bungle a few things.