Season chicken breast with salt and pepper and set aside.
Add rice, chicken broth, diced onion, smashed garlic, oregano, and basil to the crockpot. Stir to combine.
Place the chicken on top of the rice mixture and drizzle with the juice of half the lemon. Cover and cook on HIGH for 2 hours or LOW for 4-6 hours.
In the final 30 minutes of cooking, add broccoli florets to the crockpot. Cover and continue cooking.
Once done, remove the chicken, slice into bite-sized pieces, and return to the crockpot. Add remaining lemon juice, lemon zest, feta cheese, and parsley. Stir to combine and serve.
Notes
The chicken is fully cooked when a thermometer inserted into the thickest part reaches 165°F.