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 onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Add the chicken pieces to the skillet and cook for 5-6 minutes until lightly browned on all sides but not fully cooked through.
Stir in the uncooked rice, diced carrots, diced bell pepper, frozen peas, dried thyme, dried oregano, salt, and black pepper.
Pour the chicken broth evenly over the mixture and stir to combine.
Bring the mixture to a simmer on the stovetop.
Cover the skillet or casserole dish with a tight-fitting lid or aluminum foil.
Transfer to the preheated oven and bake for 35 minutes.
Remove the casserole from the oven and carefully remove the lid or foil.
Sprinkle the shredded cheddar cheese evenly over the top.
Return the casserole to the oven uncovered and bake for an additional 5-7 minutes until the cheese is melted and bubbly.
Remove from the oven and let it rest for 5 minutes before serving.