Step 1: Pat chicken pieces dry with paper towels and season generously all over with salt and freshly ground black pepper.
Step 2: Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Brown chicken pieces in batches, skin-side down first, until golden brown and crispy, about 5-7 minutes per side. Remove chicken and set aside on a plate.
Step 3: Reduce heat to medium. Add chopped onion and bell peppers to the pot, scraping up any browned bits from the bottom of the pot with a wooden spoon. Sauté until the vegetables have softened, about 5-7 minutes.
Step 4: Add minced garlic to the pot and cook for 1 minute more until fragrant, being careful not to burn it.
Step 5: If using, pour in the red wine and deglaze the pot, stirring and scraping any remaining browned bits from the bottom. Let it simmer for 2-3 minutes until the liquid has slightly reduced.
Step 6: Stir in the crushed tomatoes, chicken broth, bay leaf, fresh oregano (or dried), and red pepper flakes (if using). Bring the sauce to a gentle simmer.
Step 7: Return the browned chicken pieces to the pot, nestling them into the sauce. Ensure the chicken is mostly submerged in the sauce.
Step 8: Cover the pot and reduce the heat to low. Simmer for 35-45 minutes, or until the chicken is fork-tender and cooked through. Ensure internal temperature reaches 165°F (74°C).
Step 9: Remove the bay leaf from the pot. Stir in the pitted Kalamata olives (if using) and fresh chopped parsley. Taste the sauce and adjust seasoning with salt and pepper if needed.
Step 10: Serve hot, garnished with extra fresh parsley if desired. Enjoy with your favorite side dishes like pasta or polenta.