Chicken Enchiladas

• 1 tbsp extra virgin olive oil
• 1 brown onion, diced
• 500 g chicken breast, diced
• 1 capsicum, diced
• 1 zucchini, grated
• 700 g jar passata
• 30 g taco seasoning, salt reduced
• 2 cup chicken stock
• 8 mini whole wheat tortillas
• 1 cup cheese, grated