Preheat the oven to 375°F (190°C).
Grease a 9x13-inch baking dish with a little olive oil.
Sauté your veggies: Warm 1 tablespoon olive oil in a skillet over medium heat. Add diced red onion and bell pepper. Cook 4–5 minutes until softened and fragrant.
Season with a pinch of salt.
Make the creamy sauce: In a large bowl, mix salsa, Greek yogurt (or sour cream), cream cheese (if using), green chiles, 1 teaspoon chili powder, 1 teaspoon cumin, 1/2 teaspoon smoked paprika, 1/2 teaspoon garlic powder, 1/2 teaspoon salt, and a few grinds of black pepper. Stir until mostly smooth. Squeeze in half the lime juice and add a little zest if you like brightness.
Add the mix-ins: Fold in shredded chicken, black beans, corn, and the sautéed veggies.
Stir to coat everything in the sauce. Taste and adjust seasoning—add more chili powder or a pinch of salt if needed.
Prepare the base: Using corn tortillas: Cut tortillas into quarters. Spread a thin layer of the chicken mixture on the bottom of the baking dish.
Add a layer of tortilla pieces, then more chicken mixture, then a sprinkle of cheese. Repeat layers, finishing with cheese on top.
Using rice: Spread the cooked rice in an even layer on the bottom. Top with the chicken mixture and finish with cheese.
Bake uncovered for 22–28 minutes, until bubbling around the edges and the cheese is melted and lightly golden.
Rest and garnish: Let the casserole sit 8–10 minutes to set.
Sprinkle with chopped cilantro and a squeeze of lime. Add jalapeños, diced avocado, or green onions if you like.
Serve warm with a simple side salad or steamed veggies. A dollop of sour cream and a few dashes of hot sauce never hurt.