Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the chicken and season with salt and pepper. Cook through, about 5 minutes. Remove the chicken to a plate and cover.
Add the remaining 2 tablespoons of olive oil. Add in the onions and season with salt and pepper. Saute for about 2 minutes.
Next, add the zucchini, yellow squash, and can of diced tomatoes with the juices and season with salt and pepper. Cook until almost all the liquid is gone, about 3-4 minutes.
Add the garlic and stir for about 1 minute. Pour in the white wine and tomato paste. Add the oregano, basil and parsley. Stir thoroughly and cook for about 3-4 minutes to reduce the wine.
Put the chicken back in and add in the olives. Stir everything together and warm for about 2 minutes.