After his military service, Nicholas relocated to
Kentucky, and in 1821 received an appointment as U.S. Indian Agent to the
Chickasaw Nation. Nicholas later moved to
Louisiana, where he owned a
sugarcane plantation in
Terrebonne Parish while residing in
St. James Parish. He operated that plantation using enslaved labor. In the last federal census in his lifetime, Nicholas owned 236 enslaved people. Nicholas was elected as a
Jacksonian (later a
Democrat) to the U.S. Senate to fill the vacancy caused by the resignation of Senator-elect
Charles E.A. Gayarre, and served from January 13, 1836, to March 3, 1841. He was
Secretary of State of Louisiana in 1845. From 1849 to 1853 he was Louisiana's Superintendent of Education. ==Death and legacy==