coat a large skillet with cooking spray. Cook chicken and tomatoes over medium heat about 10 minutes or until chicken is no longer pink and liquid is evaporated. Set aside.
Place tortillas on flat surface. Spread equal portions of chicken mixture over half of each tortilla within 1 inch of edge. Top each with 1/2 cup cheese blend. Fold other half tortilla over filling to close.
Clean skillet; coat again with cooking spray. Cook quesadillas over medium high heat about 3 minutes on each side, or until crisp. Cut into wedges and serve.