Prepare the chicken. Season the diced chicken with garlic powder, paprika, and onion powder.
Sauté the aromatics. Combine the butter and olive oil in a large oven-safe skillet and set over medium-high heat; melt the butter. Add the onions to the skillet and cook for 2 minutes.
Brown the chicken and add the mushrooms. Add the chicken pieces to the skillet and cook for 5 minutes, or until golden brown on all sides. Stir in the mushrooms; season with salt and pepper, stir, and cook for 4 minutes, stirring frequently, until the mushrooms are tender.
Add garlic, rice, and broth. Stir in the garlic and cook for 15 seconds. Add rice and cook for 1 minute. Stir in the chicken broth and increase the heat to high; bring the mixture to a boil. Remove from heat.
Bake. Cover the skillet with a lid and bake in the oven for 30 minutes. Remove the lid and continue to bake for 3 to 4 more minutes, or until all the liquid is absorbed.
Rest and serve. Remove the chicken and rice from the oven and let stand for 5 minutes. Garnish with Parmesan cheese and parsley. Fluff and serve.