Step 1

Preheat oven to 350ºF. Coat a 9-by-13-inch baking dish with cooking spray

Step 2

Lay tortillas out on two baking sheet. Bake until just starting to harden and brown in spots, 12 to 16 minutes. Remove from the oven.

Step 3

Meanwhile, heat oil in a large non-stick skillet over medium-high heat. Add onion and cook, stirring often until softened and starting to brown, 6 to 10 minutes. Stir in Mexican spice blend and cook until fragrant, 30 seconds to 1 minute. Stir in spinach, corn and chicken and cook, stirring until heated through, 3 to 4 minutes.

Step 4

Open can of tomatoes, and stir in vinegar and salt. Spread about ½ cup of the tomato in the bottom of the baking dish. Layer a third of the tortillas over the sauce. Top with half of the chicken and corn mixture. Pour ¾ cup of the tomato mixture over the chicken and sprinkle with ½ cup cheese. Repeat with another layer of tortillas, the remaining chicen and corn mixture, ¾ cup sauce and ½ cup cheese. Top with the remaining tortillas and sauce.

Step 5

Cover with foil and transfer to the oven. Bake the casserole until heated through, steaming and bubbling around the edges, 20 to 30 minutes. Remove foil and top with the remaining ½ cup cheese and bake until the cheese is melted and bubbling, 8 to 10 minutes.