Heat a large skillet over medium-high heat with the EVOO.
Season the raw chicken with salt and freshly ground black pepper, then place in the skillet and brown on all sides.
Add the onion, celery, peppers, garlic and red pepper flakes to the skillet, and cook until tender, 3-4 minutes.
Add the balsamic vinegar, a cup or so of the chicken stock and the tomatoes to the skillet. Crush tomatoes with a potato masher and mix in the olives and raisins. Let simmer for 10-15 minutes to let the flavors blend, adding more chicken stock to reach the desired consistency of your stew.
To serve, top each portion with basil, parsley, toasted pine nuts and shaved Parmigiano Reggiano. Serve with some crusty bread alongside.