01 -
Preheat oven to 350°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
02 -
Season diced chicken with Italian seasoning, salt, and black pepper. Melt 2 tablespoons butter in a large pot over medium heat. Add chicken and cook undisturbed until golden, about 3-4 minutes per side. Remove from pot and set aside. If using rotisserie chicken, skip to next step.
03 -
In the same pot, combine chicken broth, olive oil, and uncooked rice, scraping up browned bits. Bring to a boil, then reduce heat to low, cover tightly, and simmer for 6 minutes. Add broccoli florets evenly over rice, cover, and steam for 9 minutes or until rice is tender and liquid absorbed. If undercooked, add up to 1/4 cup more broth and cook 5 minutes longer. Remove from heat and let rest, covered, for 10 minutes.
04 -
Gently stir cooked chicken, cream of chicken soup, milk, sour cream, garlic powder, dried thyme (if using), and half of the shredded cheddar into the rice and broccoli mixture. Taste and adjust seasoning with additional salt and pepper as needed.
05 -
Transfer mixture to prepared baking dish and spread evenly. Top with remaining cheddar cheese. Cover with foil and bake on center rack for 15 minutes to melt cheese and warm through.
06 -
While baking, crush Ritz crackers into coarse crumbs. Melt remaining 1 tablespoon butter and mix with cracker crumbs until evenly coated.
07 -
Remove foil from casserole and evenly sprinkle cracker mixture over surface. Return uncovered to the oven and bake for 10 additional minutes until topping is golden and cheese is bubbly.
08 -
Allow casserole to rest for 5 minutes before serving to set and facilitate clean slices. Serve warm.