She is the first woman to hold this position.
Election results showed she had won 341,504 votes, over 260,000 more than independent candidate Ratchanon Thong-aram, who won 77,057 votes and Tatchai Metto from the Progressive Movement, who won 74,531 votes.
Nantida had the support of the influential Asavahame family, which has clout in the province.