Preheat your oven to 375°F (190°C).
Pat the chicken breasts dry and season both sides with garlic powder, smoked paprika, and black pepper.
Heat olive oil in a large skillet over medium-high heat and sear the chicken for about 3 minutes per side until golden brown.
Remove the chicken and sauté sliced onions in the same skillet for 3–4 minutes until softened.
Stir in chicken broth, then add sour cream and onion soup mix until combined.
Return the chicken to the skillet and spoon sauce over it.
Sprinkle Parmesan cheese over the chicken and sauce.
Transfer the skillet to the oven and bake for 20–25 minutes until chicken reaches 165°F (74°C).
Let the chicken rest for 5 minutes before garnishing with parsley.
Serve hot alongside sides like mashed potatoes or steamed vegetables.