Preheat the oven to 375°F (190°C).
Heat olive oil in a large oven-safe skillet or casserole dish over medium heat.
Add the diced chicken pieces and cook for 4-5 minutes until lightly browned but not fully cooked through. Remove chicken and set aside.
In the same skillet, add the diced onion and cook for 3 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Add the uncooked rice to the skillet and stir to coat it with the oil and onion mixture.
Pour in the chicken broth and stir in the diced carrots, frozen peas, diced bell pepper, dried thyme, dried oregano, salt, and black pepper.
Return the browned chicken pieces to the skillet and stir gently to combine all ingredients evenly.
Bring the mixture to a simmer on the stovetop.
Cover the skillet tightly with a lid or aluminum foil and transfer to the preheated oven.
Bake for 40 minutes until the rice is tender and the chicken is cooked through.
Remove the casserole from the oven and uncover. Sprinkle shredded cheddar cheese evenly over the top.
Return the casserole to the oven uncovered and bake for an additional 5-10 minutes until the cheese is melted and bubbly.
Remove from the oven and let rest for 5 minutes before serving.