Nantes entered provincial politics in the 1978 election, winning the Cole Harbour riding.[4] He was re-elected in 1981.[5] On November 4, 1983, Nantes was appointed to the Executive Council of Nova Scotia as Minister of Labour.[6][7] Nantes was re-elected in the 1984 election,[8] and continued to serve in the Labour portfolio until moving to Minister of Municipal Affairs in a November 1985 cabinet shuffle.[9][10] In November 1987, Nantes was shuffled to Minister of Small Business Development.[11][12]
In the 1988 election, Nantes was re-elected for a fourth term, defeating Liberal Alan Mitchell by 1400 votes.[13] In a post election cabinet shuffle, he was named Minister of Health.[14] On September 25, 1990, Nantes resigned from cabinet after Halifax police charged him with releasing confidential mental health information about a former deputy minister who had made allegations of widespread patronage in the Tory government.[15][16] An initial investigation of Nantes's remarks found that no charges could be laid as he was protected by parliamentary privilege,[17] but the case was reopened when the local CBC station broadcast similar comments made by Nantes to reporters outside the legislature.[18] Nantes went on trial in January 1991,[19] and was acquitted of the charges in March 1991.[20][21]
On January 22, 1993, Nantes announced that he was not running for re-election in the 1993 election.[22]