Spray the inside of the crockpot with nonstick cooking spray to prevent sticking.

Chop the chicken breasts into bite-sized pieces and finely chop the onion and mince the garlic.

Rinse the rice under cold water until the water runs clear, then drain well.

Cut the broccoli into small florets and set aside.

In the crockpot, combine the chicken pieces, broccoli florets, chopped onion, minced garlic, and rinsed rice.

In a separate bowl, whisk together the chicken broth, milk, condensed cream of mushroom soup, shredded cheddar cheese, salt, pepper, and dried thyme until smooth.

Pour the sauce mixture evenly over the ingredients in the crockpot without stirring.

Cover and cook on low for 4 hours, or until the chicken is cooked through and the rice is tender.

Once cooking is complete, sprinkle the remaining 1/4 cup shredded cheddar cheese over the top, cover, and let it melt for about 5 minutes.

Garnish with chopped fresh parsley if desired before serving.