Summer Vegetable Chicken Tortilla Casserole

Arrange racks in top and bottom third of oven; preheat to 450 degrees F. Coat two rimmed baking sheets and a 9-by-13-inch baking pan with cooking spray.

Combine eggplant, onions, corn, 1 1/2 tablespoons oil, 1/4 teaspoon salt and 1/4 teaspoon pepper in a medium bowl. Transfer to one of the prepared baking sheets (reserve the bowl). Roast on the bottom rack for 10 minutes. Combine chicken, zucchini (or squash), garlic and the remaining 1 1/2 tablespoons oil, 1/4 teaspoon salt and 1/4 teaspoon pepper in the reserved bowl. Transfer to the second prepared baking sheet.

Move the baking sheet with the eggplant to the top rack and place the baking sheet with the chicken on the bottom rack. Roast until the chicken is cooked through and all the vegetables are soft and starting to brown, about 15 minutes. Shred the chicken and transfer it along with the vegetables to a large bowl; stir in 1 cup enchilada sauce. Reduce oven temperature to 400 degrees F.

Arrange 6 tortilla halves on the bottom of the prepared baking pan. Top with 1 1/2 cups of the chicken mixture, then 1/2 cup cheese. Repeat with 3 more layers of tortillas and 2 more layers of the chicken mixture and cheese. Top the top layer of tortillas with the remaining 1/4 cup enchilada sauce and 1/2 cup cheese. Bake until edges are bubbling and cheese is starting to brown, 20 to 25 minutes. Let cool for 10 minutes before serving. Garnish with cilantro and serve with lime wedges, if desired.