You've never had a quesadilla like this, and it's ready in a jiffy.
Coat a large nonstick skillet with cooking spray and heat over medium heat. Add sausage; cook and stir for 2 to 3 minutes, until lightly browned. Stir in chiles.
Transfer to a bowl. Wipe skillet clean and coat with cooking spray. Heat over medium heat. Place one tortilla in skillet. Sprinkle 3 tablespoons cheese and ½ cup sausage mixture over half of the tortilla. Sprinkle with an additional 2 tablespoons cheese.
Fold tortilla in half, covering the filling. Cook for 1 to 2 minutes on each side, until lightly browned and cheese is melted. Slide onto a plate and cut into wedges. Repeat with remaining tortillas and filling. Serve with salsa and sour cream if desired.