I don't believe that your Nancy and John Augustus Ussery or included in any of the information that I have.
I have a Nancy Hobbs who was married to Thomas Usary in 1812/13 in Louisville, Claibrone County, Tennessee. She was born in about 1790 in Virginia/ Tjp,as was bprm abpit 1798 in North Carolina and moved to Tennessee (from Madison County, N.C. on the waters of the Big Ivy).
Are you able to make a connection with either of these names?
Mary Hyde Vanderslice