Season the Chicken: In a bowl, toss chicken chunks with salt, pepper, garlic powder, onion powder, and smoked paprika. Set aside.
Sear the Chicken: Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 5-7 minutes until golden brown. Remove and set aside.
Cook the Rice: In the same skillet, add rice, chicken broth, salt, and pepper. Stir, bring to a simmer, cover, and cook for 15 minutes until rice is tender.
Make the Gravy: In a separate pan, melt butter over medium heat. Add onions, garlic, and mushrooms. Sauté for 3-4 minutes until softened. Sprinkle in flour and stir for 1 minute. Slowly whisk in milk and cream until thickened. Add thyme, ground mustard, and red pepper flakes. Simmer for 2-3 minutes.
Combine Everything: Return chicken to the skillet with rice. Pour gravy over the top and stir to combine. Cover and simmer for 5 minutes.
Serve & Enjoy: Garnish with parsley and Parmesan. Serve hot!