In a 4- or 5-qt. slow cooker, add stock, carrots, onion, rice, peas and basil; stir to combine. Sprinkle chicken with salt and pepper; layer on top of the rice mixture. Cook, covered, on low until a thermometer inserted into chicken reads 170°-175°, 4-5 hours.
Remove chicken. When cool enough to handle, remove meat from bones; discard bones. Shred meat with two forks; return to slow cooker. Heat through. If desired, serve with Parmesan cheese.