Police Lieutenant Scott Nix has been named the town’s new police chief. The appointment took effect July 11. Nix has been the town’s interim police chief since early May, when Richard Glavin resigned from the position after his arrest on drunken driving and assault charges in his hometown of Tyngsborough. Glavin was off duty at the time but was driving a Sudbury-owned vehicle. “I am humbled and honored in being selected to lead the Sudbury Police Department,’’ Nix said in a prepared statement. “I’m proud of the department personnel and appreciative of their support, and I’m excited to work with everyone moving forward in a positive manner.’’ Nix is a longtime Sudbury resident and has risen through the town force’s ranks, starting as a police dispatcher in 1993. He has been a lieutenant since 2004. He served in the Marine Corps from 1991 to 1997, and received several military awards. A swearing-in ceremony will be held at 7:15 p.m. July 30 in Town Hall prior to the Board of Selectmen’s regular meeting.