Preheat the oven to 375°F (190°C).
In a large oven-safe casserole dish, heat 2 tablespoons of olive oil over medium heat.
Add the chopped onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for an additional 1 minute until fragrant.
Add the chicken thigh pieces to the casserole dish and cook for 5-6 minutes, stirring occasionally, until lightly browned but not fully cooked through.
Add the diced red and green bell peppers and cook for 3 minutes until slightly softened.
Stir in the rinsed rice, dried oregano, dried thyme, black pepper, and kosher salt, mixing well to combine all ingredients.
Pour in the chicken broth and fresh lemon juice, stirring gently to distribute evenly.
Scatter the cherry tomato halves and sliced Kalamata olives over the top of the mixture.
Cover the casserole dish tightly with aluminum foil and bake in the preheated oven for 35 minutes.
Remove the foil and sprinkle the crumbled feta cheese evenly over the casserole.
Return the casserole to the oven, uncovered, and bake for an additional 10-15 minutes until the rice is tender and the chicken is cooked through.
Remove from the oven and let the casserole rest for 5 minutes before serving.
Garnish with chopped fresh parsley and serve warm.