According to Baidu map query, it takes 2 hours and 50 minutes to drive from Dazhou, Sichuan via Baomao Expressway, Huyu Expressway and Inner Ring Expressway to Chongqing, with a total distance of 227.6 kilometers.
You can also take the C725 train in Dazhou19: 40-21:51and get off at Chongqing North Railway Station. The whole journey takes 2 hours, 1 1 minute.