Assemble Enchilada Bake
Spray a 9x13 baking dish with cooking spray and set aside.
Preheat oven to 375°.
Heat 1 Tbsp olive oil in a saute pan. Add 1 diced onion and saute until soft - approx 5 min. Add 1 clove minced garlic and saute for 1 minute more until fragrant.
Add 2 cups shredded chicken and 1 1/2 cup enchilada sauce to the onion mixture and stir until combined and heated through. Set aside.
Pour ½ cup of enchilada sauce in the bottom of a 9 x 13 casserole dish. Add a layer of tortillas, a layer of chicken mixture and a layer of cheese, if using. Repeat with another layer and finally a third layer topped with remaining ½ cup enchilada sauce and cheese.
Cover the baking dish with aluminum foil and bake for 30 minutes. Remove foil and bake an additional 10 minutes until the top layer of cheese is melted and bubbly.
Remove from the oven and let cool for a few minutes before serving.
Serve with roasted vegetables for Whole30/ Paleo, or rice and beans.