Slice each chicken breast in half horizontally to make 4 thin cutlets, then season both sides with garlic powder, onion powder, Italian seasoning, salt, and black pepper.
Dredge each seasoned cutlet in the flour, shaking off any excess.
Heat the olive oil in a large heavy-duty skillet over medium-high heat.
Add the chicken cutlets to the skillet and cook 3–4 minutes per side, until golden and cooked through; transfer to a plate and set aside.
Reduce heat to medium, add the butter to the same skillet, then sauté the chopped garlic about 1 minute until fragrant.
Whisk in the ranch seasoning, then pour in the chicken broth and heavy cream; bring to a simmer and cook until slightly thickened, about 2–3 minutes. Taste and adjust salt and pepper if needed.
Return the chicken to the skillet and spoon the sauce over the cutlets to heat through, about 1–2 minutes.
Serve the creamy ranch chicken with your choice of mashed potatoes, rice, pasta, or vegetables.