Preheat the oven to 400°F. Grease a 9x13 inch baking dish.
In a large skillet, heat avocado oil over medium-high heat. Add chicken pieces and cook until browned, about 5-7 minutes.
Add sliced bell peppers, and onion slices to the skillet. Cook, stirring occasionally, until the vegetables are tender, about 8 minutes. Add the garlic and cook for 30 45 seconds until fragrant.
Stir in the drained diced tomatoes with green chiles.
In a separate bowl, mix together the softened cream cheese, sour cream, taco seasoning, oregano, salt, and pepper until well combined.
Add the cream cheese mixture to the skillet with the chicken and vegetables. Stir until evenly coated and heated through.
Transfer the chicken and vegetable mixture to the prepared baking dish. Sprinkle shredded Mexican blend cheese evenly over the top.
Bake in the preheated oven for 15-20 minutes, or until the cheese is melted and lightly golden brown.
Remove from the oven and let cool for 5 minutes. Garnish with chopped fresh cilantro, if desired.