His first documented court appearance concerned announcement that he would settle the estate of his wealthy half-brother Lewis Burwell, who has been a burgess for Gloucester county before being appointed to the Governor's Council and briefly serving as its president before his death in 1756.
In late 1755, York County voters first elected Nicholas as one of their representatives in the House of Burgesses, a part-time position, and he took his seat in March 1756, then won re-election in 1758, serving from 1756 to 1761.
[6] During this term, the Governor's Council appointed Nicholas to the committee of correspondence, where he served with Peyton Randolph, George Wythe and John Robinson even when not a burgess.
In fact, in 1774 Jefferson had to rewrite a motion written by Nicholas objecting to the next Royal Governor Lord Dunmore's land proclamation.
[11][12] On December 13, 1775, after the battle of Great Bridge, Nicholas introduced a motion in the House of Burgesses denouncing Lord Dunmore as champion of "tyranny" a monster, "inimical and cruel" for pronouncing martial law and assuming powers, the "King himself could not exercise."
Two days later he also submitted a motion to grant pardons to black slaves who he claimed had been deluded by the British to join Loyalist forces.
In 1779 fellow legislators appointed Nicholas to the high court of chancery, where he served with his mentor George Wythe, as well as Edmund Pendleton and John Blair.
His elder brother George Nicholas (1754-1799) served in the Continental Army and Virginia legislature, but declined the post of U.S.Attorney for the District of Kentucky.
[16] His son (this man's grandson), Robert C. Nicholas moved to Kentucky and eventually became a United States Senator from Louisiana.
His sister (this man's daughter) Elizabeth (1753–1810) married Edmund Randolph, a Virginia lawyer who became Governor and later the first United States Attorney General.
But he appeared to many who did not thoroughly understand him, to be haughty and austere; because they could not appreciate the preference of gravity for levity, when in conversation the sacredness of religion was involved in ridicule or language forgot its chastity."