Sprinkle the chicken with salt and pepper. Heat the oil in a large braiser or high-sided saute pan oven over medium-high heat. Add the chicken skin-side down and cook, undisturbed, until golden brown, 3 to 4 minutes. Remove the chicken to a plate.
Reduce the heat to medium-low and add 1 tablespoon butter along with the onions, garlic and crushed red pepper. Cook, stirring often, until softened, about 5 minutes. Add the wine and simmer until reduced by about half, about 3 minutes. Add the tomatoes, olives, oregano and the remaining tablespoon butter and bring to a simmer; season with salt and pepper.
Nestle the chicken in the sauce skin-side-up and transfer to the oven. Bake until the chicken is just cooked through, about 40 minutes. Sprinkle with the parsley and serve immediately.