Preheat the oven to 180°C (350°F).
Grease a large casserole dish with olive oil. Season the chicken pieces with salt and black pepper and place them in the dish.
Add the diced potatoes, sliced carrots, bell pepper, zucchini, onion, and garlic on top of the chicken.
Mix the chicken stock with tomato paste and pour over the casserole.
Sprinkle with thyme, salt, and black pepper.
Cover with a lid or aluminum foil and bake for 1 hour, until the vegetables are tender and the chicken is fully cooked.
Garnish with fresh parsley before serving.