In a large skillet over medium heat, heat 1 tablespoon oil. Season chicken with paprika, salt, and pepper and cook until golden and no longer pink, 8 minutes per side. Transfer to a plate.
Heat remaining tablespoon oil. Add onion and cook until soft, 5 minutes, then add garlic and cook 1 minute more. Add spinach, in batches, until wilted.
Pour over the heavy cream and chicken broth and simmer 3 minutes. Add mozzarella and Parmesan and stir until melted, then return chicken to skillet and simmer 5 minutes.
Serve creamed spinach spooned over chicken with bread, if using.