Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add onion; sauté 5 minutes or until lightly browned. Add garlic; sauté 1 minute. Add squash; cook 30 seconds. Transfer mixture to a medium bowl; stir in beans. Add broth and enchilada sauce to pan; bring to a boil. Reduce heat, and simmer 5 minutes, stirring occasionally. Set aside.
Place half of tortilla strips in bottom of an 11 x 7-inch baking dish coated with cooking spray. Layer half of squash mixture over tortillas; top with remaining tortillas and chicken mixture. Pour broth mixture evenly over chicken mixture. Sprinkle with cheese. Bake at 450° for 10 minutes or until tortillas are lightly browned and cheese is melted.
Serve warm (and optional – sprinkled with fresh diced avocado, tomatoes and cilantro)