Preheat the oven to 350 degrees.
Heat a large deep skillet over medium-high heat and add olive oil. Saute the bell pepper, garlic, and onion, stirring occasionally, until the onion is translucent and the pepper is tender.
Stir in the chicken, cream cheese, sour cream, and about half of the enchilada sauce.
Mix in half of the tortillas pieces, reserving the rest for the top.
After mixing the tortilla pieces with the chicken mixture, add the remaining tortillas to the top of the casserole. Pour the remaining enchilada sauce over the tortillas and sprinkle with the cheese.
Bake for 20 to 30 minutes or until the edges are bubbly and the cheese has melted.
Garnish with diced tomatoes and chopped cilantro.