Rinse chicken thighs under cold running water and pat dry with paper towels. Season the thighs all over with salt and pepper. In a shallow, heavy-bottomed pan heat the oil on medium-high. Add the thighs, skin side down, and cook until golden brown, about 4 minutes per side. If you need more space, cook them in two batches. Remove to a plate and set aside. Drain off all but 1 tablespoon of oil.
Reduce the heat to medium and add the onion and garlic to the pan. Cook, stirring often, until soft and translucent, about 5 minutes. Pour in the white wine to deglaze the pan, scraping up any brown bits that may have accumulated on the bottom. Simmer to reduce the liquid until almost evaporated, about 4 minutes.
Add back the chicken thighs, nestling them together, then sprinkle in the olives, capers and chili flakes (if using). Pour in the Rao’s Homemade Arrabbiata sauce, chicken stock and oregano. Gently stir to combine. Bring to a simmer and cook, partially covered, until the chicken is cooked through, 15 to 20 minutes.
Transfer the thighs to a large shallow bowl or rimmed platter, pour the sauce over top and sprinkle with parsley before serving.