Preheat the oven to 375°F (190°C).
In a medium saucepan, combine Knorr Rice Sides Chicken flavor mix, 1 1/2 cups water, and 1 1/2 cups milk. Bring to a boil over medium-high heat, then reduce heat to low and simmer, covered, for 15 minutes or until rice is tender and liquid is absorbed.
While the rice cooks, heat olive oil in a large skillet over medium heat.
Add the bite-sized chicken pieces to the skillet. Season with salt, black pepper, garlic powder, and onion powder.
Cook the chicken, stirring occasionally, until fully cooked and no longer pink in the center, about 7-8 minutes. Remove from heat.
In a large mixing bowl, combine the cooked rice, cooked chicken, shredded cheddar cheese, shredded mozzarella cheese, and sour cream. Stir until well combined.
Transfer the mixture to a greased 9×9-inch baking dish and spread evenly.
Sprinkle the grated Parmesan cheese evenly over the top of the casserole.
Bake uncovered in the preheated oven for 20 minutes or until the cheese is melted and bubbly and the casserole is heated through.
Remove from the oven and let it rest for 5 minutes before serving.