Pound the chicken breasts to an even 1-inch thickness, then generously season both sides with salt and pepper.
In a pan over medium-high heat, melt 1 tablespoon of butter along with olive oil. Sear the chicken for 4-5 minutes on each side until golden brown. Transfer to a plate and set aside.
Lower the heat to a simmer and melt the remaining butter in the same pan. Stir in flour, cooking for about one minute.
Slowly pour in the chicken broth, scraping up any browned bits from the bottom of the pan to enhance the flavor.
Add milk, sour cream, onion powder, garlic powder, Italian seasoning, and ranch seasoning mix. Stir well until the sour cream and seasoning are fully incorporated into the sauce.
Return the chicken and any plate juices to the pan, spooning the sauce over the chicken. Let the chicken simmer in the sauce until it’s warmed through and the sauce has slightly thickened.
Serve hot, optionally garnished with fresh parsley. Enjoy!