Preheat your oven to 375°F (190°C).
Season chicken thighs generously with salt and pepper.
In an oven-safe skillet, heat olive oil over medium-high heat. Add chicken thighs, skin side down, and cook until golden brown, about 5 minutes per side. Remove and set aside.
In the same skillet, add chopped onion and minced garlic. Sauté until fragrant and translucent, about 3 minutes.
Stir in diced tomatoes, chicken broth, butter, dried thyme, and dried rosemary. Let it simmer for 5 minutes, allowing the flavors to meld.
Return the chicken thighs to the skillet, skin side up, and spoon some tomato mixture over them.
Transfer the skillet to the preheated oven and roast for about 40-45 minutes or until the chicken reaches an internal temperature of 165°F (74°C) and the skin is crispy.
Garnish with fresh basil leaves before serving.