Heat a splash of olive oil in a large heavy-based pot and set to high heat. Season the chicken with a little salt and pepper and brown in batches. Remove and set aside.
Add a little more olive oil to the pot and add the pancetta or bacon. Cook, stirring, until crisp.
Add the onion, carrot, celery, capsicum and chilli. Lower heat to medium and cook, stirring often, until vegetables have softened.
Add the mushrooms and cook until tender.
Add the garlic, thyme and oregano and cook another minute, stirring, until the garlic is fragrant.
Increase the heat and add the tomato paste. Cook for one minute while stirring consistently.
Pour in the wine and stir as it bubbles away, dislodging any browned bits that have stuck to the bottom of the pot. Keep stirring until the wine has been reduced by half.
Return the browned chicken to the pot, add the crushed tomatoes, passata and basil and stir everything to combine. Add a good pinch of salt and a grinding of black pepper and keep stirring everything together until the liquid is boiling.
Reduce heat, place lid on, and simmer for 30 minutes. The chicken should be almost all submerged in the sauce, top up with a little water if you need to.
After 30 minutes simmering, remove the lid and increase heat to medium and cook for another 15 minutes, or until the sauce has thickened and the chicken is cooked through.
Remove from heat, stir in the olives, and sprinkle with parsley to serve.