Preheat oven to 350°F (175°C).

Prepare a large casserole dish or a 9x13-inch cake pan.

In a bowl, combine mushroom soup, cream of chicken soup, chopped Ro-Tel, garlic salt, and chili powder.

Chop the onion and bell pepper, and add them to the soup mixture.

Shred the Velveeta cheese and add it to the soup mixture. Mix well.

Place the whole chicken in the prepared casserole dish.

Pour the soup and cheese mixture over the chicken, ensuring it's evenly coated.

Crush the plain Doritos and sprinkle them over the top of the casserole.

Shred the Mozzarella cheese and sprinkle it over the Doritos.

Bake in the preheated oven for 60 minutes, or until the chicken is cooked through and the cheese is melted and bubbly.

Let cool slightly before serving.