In a large skillet, scramble-fry sausage in olive oil; drain on paper towels. Add another Tbsp oil to skillet; saute onion & pepper about 3-4 minutes then add tomatoes, zucchini, garlic & lemon zest. Season with salt, pepper & Italian seasoning & cook 3-4 minutes more. Gently stir in squash, cooked chicken & sausage & remove from heat.