For the cacciatore, heat the olive oil in a frying pan on the stove over medium heat. Add the onion and cook it for 5 minutes, until it becomes golden brown.
Add the tomato sauce and mix it in with a wooden spoon (the onion should be completely covered).
Stir in the olives.
Add the chicken and stir the whole mixture so that the ingredients are mixed well.
Cook the mixture over medium heat for 5 minutes, then add the carrots and zucchini. Mix everything well and cover the pan with a lid.
Cook the mixture for 10 minutes, checking halfway through to make sure there’s enough liquid in the bottom of the pan and the mixture isn’t burning. The mixture will be very smooth, with the tomato having become creamy, and the chicken will be cooked (165 degrees F on an instant-read thermometer). At this point, reduce the heat to low and add the parsley, salt, pepper, and garlic powder.
Cook the mixture, uncovered, over low heat for 5 minutes, stirring frequently, to allow the seasonings to blend.
Serve the cacciatore hot, topped with the parsley sprigs. Best enjoyed with bread and olive oil.