Season the chicken with salt, pepper, garlic powder, and onion powder.
(Optional) Heat olive oil in a skillet and sear the chicken briefly until lightly browned; transfer to the slow cooker.
In a bowl, combine uncooked rice, chicken broth, fresh lemon juice, dried thyme, and dried oregano; mix well.
Pour the rice and broth mixture over the chicken in the slow cooker.
Place lemon slices on top for extra citrus aroma.
Cover and cook on low for 6–7 hours or on high for 3–4 hours until the chicken is fully cooked and the rice is tender.
About 30 minutes before serving, check doneness and adjust seasoning if needed.
Remove chicken, fluff the rice with a fork, and either shred the chicken or serve it whole over the rice.
Sprinkle with fresh parsley before serving.