Preheat your oven to 375°F (190°C) and lightly grease a small oven-safe baking dish.
Dice the chicken breast into bite-sized pieces and season with sea salt, black pepper, and garlic powder.
Heat the olive oil in a skillet over medium heat and sauté the diced red bell pepper until slightly softened, about 3 minutes.
Add the chicken to the skillet and cook until browned and cooked through, then stir in the baby spinach until just wilted.
In a small bowl, whisk together the red enchilada sauce and Greek yogurt until smooth and creamy.
Slice the corn tortilla into thin strips.
In the baking dish, layer half of the tortilla strips, followed by the chicken and vegetable mixture.
Pour the creamy enchilada sauce evenly over the chicken and top with the remaining tortilla strips.
Sprinkle the shredded cheddar cheese over the top.
Bake for 15-20 minutes until the sauce is bubbling and the cheese has melted into a golden crust.
Let rest for 5 minutes before serving to allow the sauce to set.