His uncle died on 12 January 1753 and Nesbit inherited his business, his estate at Icklesham and his political connections with the Pelham family.
[1] Lord Sandwich allowed Nesbitt to take over his uncle's seat as Member of Parliament for Mitchell at a by-election in 1753 and was prepared to support him again in 1754 but Henry and James Pelham insisted upon his standing then at Winchelsea.
He had interest in a Dublin bank with George Colebrooke, and he was underwriting Government loans on a large scale.
Although he had purchased the borough and hundred of Cricklade in 1764, he was defeated there at the general election of 1768, and only re-entered Parliament for Winchelsea in a by-election in January 1770.
After the outbreak of the American War, the size of the contracts was doubled and he received a grant of 20,000 acres in St John's Island.