Heat the olive oil in a large skillet over medium-high heat. Add the diced chicken breasts, seasoned with salt and pepper.
Remove the chicken from the skillet and set aside. In the same skillet, add the diced onion and cook until translucent, about 5 minutes.
Add minced garlic and sliced mushrooms to the onions. Sauté for another 5–7 minutes, until the mushrooms are browned and tender.
Sprinkle the flour over the mushroom mixture, stirring to coat evenly. Cook for 1 minute to cook off the raw flour flavor.
Gradually pour in the chicken broth while stirring, ensuring no lumps form. Bring the sauce to a simmer.
Lower the heat and stir in the sour cream, mixing until the sauce is creamy and well combined. Return the chicken to the skillet.
Simmer for an additional 5 minutes until the chicken is cooked through and heated. Adjust seasoning with salt and pepper as needed.
Serve the creamy chicken stroganoff over your choice of egg noodles, rice, or mashed potatoes, garnished with chopped parsley.
