In small bowl, combine bell peppers, tomatoes and chiles; mix well. Spoon about 1/3 cup pepper mixture and heaping 1/3 cup cheese onto each of 8 tortillas. Top with remaining tortillas.
Spray large nonstick skillet with nonstick cooking spray. Heat over medium heat until hot. Add quesadillas 2 at a time; cook 1 to 2 minutes on each side or until cheese is melted and tortillas are toasted.
To serve, cut each quesadilla into wedges. Serve with salsa and sour cream.