Prepare the slow cooker by coating it with a light coating of cooking spray.
Add the uncooked brown rice, chopped onion, salt, black pepper, granulated garlic, and Italian seasoning to the slow cooker and mix to combine.
Stir in the condensed cream of chicken soup and chicken stock until well blended.
Season the chicken breast cubes with a pinch of salt and pepper, then add them to the slow cooker, ensuring they are evenly distributed.
Cover and cook on low for 2 hours.
After 2 hours, add the chopped broccoli to the slow cooker, stirring gently to combine. Cover again and cook for an additional 2 hours on low.
Once the cooking time is complete, stir in the shredded mild cheddar cheese until melted and fully incorporated.
Serve warm and enjoy!