Hi Margaret, I cannot find William Nesbit in Hancock County, but there is a William Nesbit with wife Isabel in Adams County, IL in the 1840-1870 census records, and their son William Matthew is there until his death in 1916.
1840 Quincy, Adams County William R. Nesbit one male 20-29 one female 30-39
1850 Lima, Adams County William R. Nesbit age 35 born KY Isabella age 30 born KY Mary age 8 born IL William M age 4 born IL
1860 Lima, Adams County William R. Nesbit age 44 born KY Isabel age 47 born KY Mary age 18 born IL William M age 14born IL Jenny Nesbit age 43 born KY
1870 Lima, Adams County William R. Nesbit age 56 born KY Isabella age 56 born KY Ida Hutts age 16 born IL Jerrey Hutts age 54born KY
William Matthew Nisbit IL Death Index born 5 April 1846 Lima, Adams County died 23 Feb 1916 Lima, Adams County father William R Nisbit mother Isabella Archer
buried Providence Cemetery
This couple seems to be almost a generation younger than you had indicated in your message, but they do not consistently report their ages--she starts out older than he is, but by 1870 he's caught up.
I don't find either of them in the 1880 census. Findagrave has no listings for them in Adams County. Their daughter Mary apparently married Albert Cory May 21, 1865 (IL Sec of State marriage index) in Adams County, and by 1870 they are in Tama County, Iowa.
This could just be coincidence that another William R. Nesbit with a wife named Isabel, both born in KY happens to live in a county that borders Hancock County, but I thought I would pass the information along for you to check into.