Season chicken with salt, pepper, garlic powder, and paprika.
Heat olive oil in a skillet over medium heat. Cook chicken for 5–6 minutes per side until golden and cooked through. Remove and set aside.
In the same skillet, melt butter. Stir in flour and cook for 1 minute.
Slowly whisk in chicken broth (and milk if using). Stir until smooth.
Simmer gravy until thickened. Add salt and pepper to taste.
Return chicken to the pan and coat with gravy.
Let simmer for 5 minutes. Garnish with parsley and serve warm.