Preheat and prep: Heat your oven to 375°F (190°C). Lightly spray a 9x13-inch baking dish with nonstick spray.
Sauté vegetables: In a large skillet, heat olive oil over medium.
Add onion and bell pepper with a pinch of salt. Cook 5–6 minutes until softened. If the pan gets dry, splash in a bit of broth.
Season the mix: Stir in cumin, chili powder, smoked paprika, and garlic powder.
Cook 30 seconds until fragrant.
Add beans and corn: Stir in black beans and corn. Cook 2 minutes to warm through. Remove from heat.
Make the lightened sauce: In a bowl, whisk enchilada sauce with Greek yogurt and 1/2 cup broth until smooth.
Season with salt and pepper. The sauce should be pourable, not watery.
Combine with chicken: In a large bowl, toss shredded chicken with half of the sauce and half of the cilantro. This keeps the chicken juicy as it bakes.
Layer the bake: Spread a thin layer of the remaining sauce on the bottom of the dish.
Add a layer of tortillas (tear or overlap to cover). Spoon on half the chicken, then half the bean-corn mixture, then a third of the cheese.
Repeat: Add another layer of tortillas, the rest of the chicken, the rest of the bean-corn mixture, and another third of the cheese.
Top and bake: Finish with a final layer of tortillas, the remaining sauce, and the remaining cheese. Cover loosely with foil and bake 20 minutes.
Uncover and finish: Remove foil and bake 10–12 more minutes, until bubbly and lightly browned at the edges.
Rest and garnish: Let it rest 10 minutes to set.
Sprinkle with remaining cilantro. Add optional toppings like jalapeños, avocado, and a squeeze of lime.
Serve: Slice into squares and serve warm. Great with a simple side salad or roasted veggies.