Combine first 3 ingredients, stirring well. Heat oil in a large nonstick skillet over medium-high heat. Sprinkle the spice mixture evenly over chicken. Add chicken to pan; sauté for 3 minutes. Add onion, corn, and zucchini to pan; sauté for 2 minutes or until chicken is done. Stir in salsa and 2 tablespoons cilantro. Cook 2 minutes or until liquid almost evaporates, stirring frequently.
Working with 2 tortillas at a time, arrange tortillas in a single layer on a baking sheet; lightly coat tortillas with cooking spray.
Broil 3 minutes or until lightly browned. Spoon about 3/4 cup chicken mixture in the center of each tortilla; sprinkle each serving with 1/4 cup cheese. Broil an additional 2 minutes or until cheese melts. Repeat procedure with remaining tortillas, chicken mixture, and cheese. Sprinkle each serving with about 3/4 teaspoon of remaining cilantro. Serve immediately.