Place the chicken breasts in the bottom of a 6-quart slow cooker.
Pour in the chicken broth and sprinkle evenly with garlic powder, onion powder, and black pepper.
Cover and cook on LOW for 6-7 hours or HIGH for 3-4 hours, until the chicken is tender and shreds easily.
Remove the chicken and shred it using two forks. Return the shredded chicken to the slow cooker.
Add the softened cream cheese and shredded cheddar cheese to the pot. Stir continuously until the cheeses are fully melted and combined into a creamy sauce.
Cover and cook on LOW for an additional 10-15 minutes to let the flavors meld.
Serve the creamy chicken generous ladled over cooked white rice.
Top with halved cherry tomatoes and sliced green onions immediately before serving.