1. In medium bowl, mix cheese, chicken, green scallion, corn , avocado 1/3 cup salsa and the squash purée.
2. Sprinkle tortilla with cooking spray on one side; place sprayed side on a 10-inch pan. Operates with a quarter of the chicken mixture. Top with another tortilla; spray the top of the tortilla with cooking spray.
3. Golden brown over medium heat for about 2 minutes or until. Turn quesadilla with more care; cook 1-2 minutes or until golden brown. Repeat with the remaining tortillas and chicken mixture. To serve, cut into quarters quesadillas. Serve with salsa and sour cream.