Pat the chicken breasts dry with paper towels. In a small bowl, mix 1/2 tsp salt, 1/4 tsp black pepper, garlic powder, and paprika. Rub this seasoning blend evenly over both sides of each chicken breast. Heat the olive oil in a large skillet over medium-high heat. Once hot, add the chicken and cook for 5-6 minutes per side, until deeply golden brown and cooked through (internal temperature of 165°F). Transfer the chicken to a plate and set aside.
Reduce the heat to medium. Add the butter to the same skillet. Once melted, add the diced onion and cook for 3-4 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for 1 more minute until fragrant.
Pour in the chicken broth to deglaze the pan, scraping up any remaining bits. Let it simmer for 2 minutes to reduce slightly. Stir in the heavy cream, Parmesan cheese, dried thyme, onion powder, and the remaining 1/2 tsp salt and 1/4 tsp black pepper. Bring the sauce to a gentle simmer and cook for 3-4 minutes, stirring frequently, until it thickens slightly and the cheese is fully melted.
Return the cooked chicken breasts to the skillet, nestling them into the creamy sauce. Spoon some of the sauce over the top of each piece. Reduce the heat to low, cover the skillet with a lid, and let it simmer gently for 5 minutes. This allows the chicken to reheat and absorb the sauce flavors.
To serve, spoon a generous portion of warm cooked rice onto each plate. Place a smothered chicken breast on top of the rice. Ladle plenty of the creamy sauce over the chicken and rice. Garnish generously with the chopped fresh parsley and serve immediately with a lemon wedge on the side for a bright squeeze, if desired.