Set the oven rack to the lower third position. Preheat to 350ºF (177ºC).
Trim any excess fat or skin from the chicken thighs. In a small bowl, combine 1 teaspoon salt and ½ teaspoon pepper. Generously season both sides of the chicken.
Heat a large 12-inch oven-proof skillet or dutch over medium-high heat. Add 1 tablespoon olive oil. Once hot, carefully add in the chicken thighs, skin-side down. Sear for 5 minutes until crispy and browned. Flip and cook for 2 minutes, turn off the heat. Transfer to a clean plate, leave 2 tablespoons of the fat drippings in the pan. Alternatively, drain the drippings and add 2 tablespoons of olive oil to the pan.
Heat the skillet over medium heat. Add the onions, garlic, and Italian seasonings. Saute for 2 minutes until the onions are crisp-tender. Add the red and green bell peppers, saute for 1 minute. Add the tomato paste and saute for 1 minute.
Add the wine. Stir and simmer until almost completely evaporated, about 1 to 2 minutes.
Stir in the crushed tomatoes, diced tomatoes with the juice, chicken broth, and capers. Stir in the mushrooms.
Add the chicken back to the pan, turn to coat in the sauce, and leave it skin-side facing up, simmer for 5 minutes.
Cover the skillet with a lid and carefully transfer the pot to the oven. Cook until the meat is very tender, about 60 minutes. Season sauce with salt and pepper to taste. Garnish with parsley and basil, serve hot.
Notes
Using Chicken Breasts: Check the chicken after 10 minutes of braising, and then every 5 minutes after, until the internal temperature reaches 160 to 165ºF (71 to 74ºF).
Using Red Wine: Use a dry red wine like Chianti or pinot noir.
Stovetop Braising: After simmering the sauce for 5 minutes, cover and reduce heat to low. Stir the sauce every 10 minutes to prevent burning on the bottom of the pan. Cook until the meat reaches 170ºF (77ºC).
For a Thicker Sauce: Transfer the chicken to a serving platter, cover with foil to keep warm. Heat the sauce over medium-high heat, stir and cook until the sauce reduces to the desired consistency.
For a Spicy Sauce: Add ⅛ to ¼ teaspoon of red pepper flakes when sauteing the Italian seasonings in the fat.