At the end of the war, he returned to London and lobbied for a grant of land in Nova Scotia. He became part of a group of loyalists urging that Nova Scotia be partitioned, which led to the creation of New Brunswick. Chipman was named solicitor general for the new province. He prepared a charter for the city of Saint John for Governor Thomas Carleton and served as recorder for the city from 1785 to 1809, which also made him a justice of the peace. In 1785, he was one of the founders of the New Brunswick bar and set up practice in Saint John. Chipman's clients included Benedict Arnold. Also in 1785, he ran as a pro-government candidate for the Legislative Assembly and was elected, although he is said to have the support of the local sheriff in the inspection of the ballots; he was defeated in the 1793 election for the 2nd New Brunswick Legislature, but returned in Northumberland County. He was defeated again in 1795.