In a large mixing bowl, combine the shredded chicken, steamed broccoli, cooked rice, cream of mushroom soup, sour cream, garlic powder, onion powder, thyme, basil, salt, and pepper. Mix until well combined.
Transfer the mixture into a greased 9x13-inch casserole dish, spreading it evenly.
Sprinkle the shredded cheddar cheese over the top of the chicken mixture.
In a separate bowl, mix the panko breadcrumbs with olive oil until the breadcrumbs are evenly coated. Sprinkle this mixture over the cheese layer for a crunchy topping.
Bake the casserole in the preheated oven for 25-30 minutes, or until heated through and the top is golden and crispy.
Remove from the oven and let it cool for a few minutes before serving. Garnish with fresh parsley if desired.