I think your Nancy is a daughter of William Austell of 96 District, SC, said to have died Feb. 19, 1781. The name Nancy pops up in other children in that family. He had a wife named Amelia, children Joseph (d. 1823), Sally (Stacy), Amos, William, Samuel, and others most of whom moved out to Tennesse, Arkansas, etc. I think Sally Austell was born abt. 1766 so Nancy fits into that family group. Amelia, the mother, died in August 1808, those dates are from a family bible.
Check out David Austill's page at members.aol.com/elzyaust
It has never been proven, but there is good evidence that Sally Stacy, wife of Robert of Spartanburg Dist SC was an Austell. They are my line.