Step 1

Preheat oven to broil with rack 5 to 6 inches from heat. Heat oil in a large nonstick skillet over medium-high. Add zucchini, squash, and onion, and cook, stirring often, until vegetables are tender and just beginning to brown, about 10 minutes. Add garlic, and cook 1 more minute. Add chicken, salt, pepper, and 3/4 cup of the cheese; stir to combine. Cook until hot and cheese melts, about 1 minute. Remove from heat, and cover to keep warm.

Step 2

Warm tortillas according to package directions. Place about 1/3 cup of chicken mixture in center of each tortilla; fold tortilla around filling, and place, seam side down, in a lightly greased (with cooking spray) 11- x 7-inch (or a 2-quart) broiler-safe baking dish. Pour salsa over enchiladas, and sprinkle with remaining 1/4 cup cheese. Broil in preheated oven until hot and bubbly, about 1 1/2 minutes. Garnish with cilantro.