Preheat your oven to 375°F (190°C) and grease a 9×13-inch baking dish with olive oil.

In a large bowl, combine chicken breasts with 1 tablespoon of olive oil and fajita seasoning until coated.

Heat 1 tablespoon of olive oil in a skillet and sauté the seasoned chicken until browned, about 5 to 7 minutes.

In the same skillet, add remaining olive oil, bell peppers, and onion. Sauté until softened, about 5 to 6 minutes.

Blend softened cream cheese and sour cream until smooth, then stir in chicken stock, rice, vegetables, and chicken, seasoning with salt and pepper.

Pour mixture into greased baking dish, top with shredded cheese, and spread evenly.

Cover with aluminum foil and bake for 20 minutes. Remove foil and continue baking until cheese is bubbly and golden, about 10 to 15 minutes.

Let the casserole rest for 5 minutes before serving.