Preheat the oven to 350°F (175°C).
In a large skillet, heat the olive oil over medium heat.
Add the chopped onion and cook until translucent, about 3-4 minutes.
Add the minced garlic, diced red bell pepper, and diced carrots to the skillet. Cook for another 5 minutes until vegetables begin to soften.
In a large mixing bowl, combine the uncooked rice, Knorr Chicken Flavor Bouillon, and water. Stir well to dissolve the bouillon.
Add the cooked vegetables from the skillet to the rice mixture.
Stir in the shredded cooked chicken, frozen peas, sour cream, black pepper, dried thyme, and paprika until evenly combined.
Transfer the mixture to a greased 9×13 inch casserole dish and spread evenly.
Cover the casserole dish tightly with aluminum foil.
Bake in the preheated oven for 40 minutes.
Remove the foil and sprinkle the shredded cheddar cheese evenly over the top.
Return the casserole to the oven uncovered and bake for an additional 5 minutes, or until the cheese is melted and bubbly.
Remove from oven and let rest for 5 minutes before serving.