Combine first 6 ingredients (sugar through salt) in a large saucepan. Bring to a boil over medium heat; cook 10 minutes or until a candy thermometer registers 234°, stirring occasionally. Remove from heat. Add peanut butter and vanilla; stir until peanut butter melts.
Pour mixture into an 8-inch square baking pan coated with cooking spray. Sprinkle with chocolate chips. Cool for 1 hour. Cut into squares.