Start by patting the chicken thighs dry with paper towels. Season both sides generously with kosher salt and black pepper.
In a large skillet, heat the extra virgin olive oil over medium-high heat. Once hot, add the chicken thighs skin-side down. Sear for about 5-7 minutes until the skin is golden brown and crispy. Flip and cook for another 5 minutes on the other side. Remove the chicken from the skillet and set aside.
In the same skillet, add the diced onion and cook until it becomes translucent, about 3-4 minutes. Add the minced garlic and rosemary, stirring for another minute until fragrant.
Add the cubed soppressata sausage to the skillet. Cook for 3-4 minutes, allowing it to release its oils and brown slightly.
Stir in the drained and rinsed cannellini beans, ensuring they are well mixed with the sausage and aromatics.
Pour the chicken stock into the skillet and stir everything together. Bring the mixture to a simmer.
Nestle the seared chicken thighs back into the skillet, skin-side up. Cover the skillet with a lid and cook on medium-low heat for about 25-30 minutes, or until the chicken is cooked through.
Once done, remove the skillet from heat. Serve the Chicken Cannellini Bean Skillet warm, garnished with additional rosemary if desired.