Heat the olive oil in a skillet over medium heat. Brown the chicken thighs on both sides for about 3-4 minutes, then remove them from the skillet and set them aside.
In a large mixing bowl, combine the rice, diced tomatoes (including juice), chicken broth, chopped onion, minced garlic, oregano, paprika, salt, and pepper. Mix well.
Pour the rice mixture into the slow cooker.
Place the browned chicken thighs on top of the rice mixture in the slow cooker.
Cover the slow cooker with the lid and cook on low for 6 hours.
In the last 30 minutes of cooking, add the frozen peas to the slow cooker, stirring gently to incorporate.
Once cooking is complete, check the internal temperature of the chicken to ensure it has reached at least 165°F. Fluff the rice with a fork before serving.
Optional: Serve with a side salad or bread to complete the meal.