Answer: They wanted to use their land for tobacco plantations.
The Natchez are a Native American people from the Lower Mississippi Valley. They spoke a language with no known close relatives, and are noted for being the only Mississippian culture with complex chiefdoms that survived into the colonization period. The Natchez were defeated by French forces around 1730. Today, most descendants of the Natchez live in Oklahoma and South Carolina.
Initially, contact between the Natchez and the Europeans was peaceful. French colonists intermarried with the Native Americans and the French were granted some lands to cultivate. French colonists imported African slaves and cultivated tobacco plants. During the 1710s and 1720s, however, several conflicts arose. These culminated in the French commander Sieur de Chepart's order to vacate the village in order to use the land for a tobacco plantation. This initiated the Natchez Revolt.