Heat the olive oil in a large skillet over medium high heat.
Add the thyme, oregano, rosemary, Italian seasoning, garlic powder and onion powder to a small bowl, and stir to combine well.
Season the chicken with half of the seasoning mixture and salt and pepper to taste, and add it to the heated skillet.
Sear the chicken until cooked through, and remove from the skillet.
Reduce the heat to medium, and add the onion and peppers to the skillet.
Saute for 3 minutes.
Stir in the garlic, and saute for another minute.
Mix in the zucchini, mushrooms and tomatoes, and saute until the vegetables have softened.
Sprinkle with the remaining seasoning mix, and add salt and pepper to taste.
Return the chicken to the skillet, and toss to combine before serving.