Pat the chicken dry and season with a pinch of fine grain sea salt and a grind of black pepper
Over medium-high heat, add a glug of olive oil and give it a minute or so to heat up
Add the pancetta
Cook, stirring frequently until it's well browned and crisp (~ 3 minutes)
Using a slotted spoon to transfer the pancetta to a paper-towel-lined plate
Add the chicken to the skillet and sear, turning the pieces only occasionally, until it's well browned on all sides (~ 10 minutes)
Transfer them to a large plate
Pour off all but 1 Tbsp of the oil in the skillet. Add the garlic, anchovies, capers, and chili flakes to the skillet; sauté for 1 minute.
Stir in all the diced tomatoes, the basil sprig, and a pinch of fine grain sea salt, along with a grind or two of fresh black pepper
Cook, breaking up the tomatoes with a spatula until the sauce has thickened somewhat (~ 10 minutes)
While the sauce is cooking, heat the oven to 400° deg F
On a baking sheet, add the cherry tomatoes and drizzle with olive oil
Return the chicken to the skillet, transfer the skillet to the oven, and cook, uncovered until the chicken is no longer pink (~ 30 minutes)
On a separate rack in the oven, add the cherry tomatoes
Remove the cherry tomatoes from the oven and set aside
Remove the skillet from the oven and scatter the mozzarella over the chicken.
Turn on the broiler, place the skillet under the heat source, and broil until the cheese is bubbling (~ 1 to 3 minutes) ** Note: watch it carefully
Garnish the chicken with the roasted tomatoes, browned pancetta, and basil before serving