Dear Stephanie, To the best of my knowledge, Nannie did not have a sister known to be Mary; however her father, Smith PYLE had married a Hannah PARKS on 14 Apr 1836 in Nashville, TN and had a daughter whose initils were M.I. If you had dates for Mary...that might help us determine if they could be the same person.
Hannah died in Cincinnati sometime between 1840 [presuming she is the female listed with Smith and a female child under five in the 1840 census] and his marriage to Catherine SERROT in Cincinnati on 19 Oct 1845.
My notes for M.I. contain the following information:
Search of Cincinnati OH City Directories, 1850 and Earlier; Cincinnati Historical Society, Union Terminal, Cincinnati, OH, jUN 1991 by (RWE): 1842: PYLES, Smith,nailorboards Mrs. E. BATES PYLES, Isaacnailorboards Mrs. E. BATES (Mrs. Elizabeth BATES, boarding house c Front & Parsons) 1843: PYLES, Smith,nailorboards Mrs. M. WENTWORTH PYLES, Isaac,nailorboards Mrs. M. WENTWORTH (Mrs. Martha WENTWORTH, Front b Parsons & Lytle) 1849/1850 PYLES, Smith,nail cutter,Ss High e of Parsons.
1840 OH Hamilton, Cincinnati; 3rd Ward; Dw/Fam 2: Smith PYLES1 m (20-30); 1 f (under 5); 1 f (20-30); (this is presumedly(M. I.)(Hannah)
1850 OH Hamilton Co.; Cincinnati; 3rd Ward; 24 Jul; Dw175/Fam190: SmithPYLE36mnailor$300PA Catherine"22fPA M. I."13fschoolTN Ettinse"2fOH Aquilla"5/12mOH
Catherine is obviously not old enough to be M.I.'s mother, so it is presumed she is the daughter of Smith and his first wife, Hannah PARKS.
I have not found any evidence that Smith ever lived in Georgia, but in genelogy, I would not rule out anything.
There is another Smith PYLE mentioned in the annals of Chester County, PA, and also in the book by Howard Thronton PYLE of Kokomo, IN., but I do not have details re: him.
I'll try to send you a copy to your e-mail address.