Pat the chicken dry and season with salt and pepper. In a large cast-iron or other heavy skillet, heat the EVOO, 2 turns of the pan, over medium-high heat until rippling. Add the chicken and cook, turning once, until well browned, about 10 minutes. Transfer the chicken to a plate.
Add the bacon to the skillet and cook until the fat renders, about 2 minutes. Transfer to a paper towel to drain. Add the mushrooms to the skillet; cook until browned, about 5 minutes. Add the onion, cubanelle pepper, chile and garlic; season with salt and pepper. Cook, stirring, for 3 minutes. Stir in the tomato paste, then the wine. Stir in the tomatoes and stock.
Add the cooked chicken and bacon to the sauce, and simmer to cook through, 5-6 minutes. Spoon from the pan onto plates then top with the parsley (or celery tops).