After four years study, in 1847 he graduated from Dickinson College in Carlisle, Pennsylvania.
Nicholson began his career as briefly the superintendent of the free schools of Kent County in 1851. At the same time he studied law with Martin West. Bates in Dover, was admitted to the Delaware Bar in 1850, and began a law practice in Dover. In addition he served as brigadier general of militia in Kent County in 1861.
In 1864 he defeated the Republican and Ultimate Unionist candidate Nathaniel Smithers, another Dickinson graduate, and was ultimately elected as a Democrat to the 39th and 40th Congress, serving from March 4, 1865 to March 4, 1869.
During the first term he was on the Committee of Elections and in the second the Appropriations Committee. He was not a candidate for renomination in 1868 and continued his practice of the law.
His home, Wheel of Fortune, was added to the National Register of Historic Places in 1973. Elections are held the first Tuesday after November 1.
United States. Representatives took office March 4 and have a two-year term.
He was a member of the Democratic Party, who served as United States Representative from Delaware.