Preheat your oven to 375°F (190°C).
Heat the olive oil in a medium skillet over medium heat and sauté the diced bell peppers until they begin to soften.
Add the chopped spinach to the skillet and stir until just wilted, then remove the pan from the heat.
In a mixing bowl, whisk together the Greek yogurt, red enchilada sauce, sea salt, black pepper, and garlic powder until the sauce is creamy and uniform.
Stir the shredded cooked chicken and the sautéed vegetables into the sauce mixture until well coated.
Cut the corn tortillas into small strips or bite-sized squares.
In a small oven-safe baking dish, layer half of the tortilla pieces on the bottom.
Spread the chicken and vegetable mixture evenly over the tortillas, then top with the remaining tortilla pieces.
Sprinkle the shredded cheddar cheese evenly over the top layer.
Bake for 15 to 20 minutes until the cheese is melted and the sauce is bubbling at the edges.
Let the bake rest for 5 minutes before garnishing with fresh cilantro and serving.