Season chicken breasts with garlic powder, onion powder, smoked paprika, salt, and black pepper.
Heat olive oil in a large skillet over medium-high heat and sear chicken 4-5 minutes per side until golden. Remove and set aside.
Bring chicken broth and salt to a boil in a medium saucepan. Add rice, reduce heat to low, cover, and simmer 15-18 minutes until rice is tender and liquid absorbed. Fluff with a fork.
In the same skillet used for chicken, melt butter over medium heat. Whisk in flour and cook 1-2 minutes until lightly golden.
Gradually whisk in milk and chicken broth to form a smooth sauce. Stir in garlic powder, thyme, cheddar cheese, and Parmesan cheese. Cook 3-4 minutes until thickened and cheese melted.
Return chicken breasts to skillet, spoon sauce over top, cover, and simmer on low for 10 minutes until chicken is cooked through.
Serve chicken and sauce over rice, garnish with fresh parsley, and serve immediately.