Add remaining dressing, zucchini, peppers and onions to centre of skillet; cook and stir 6 min. or until crisp-tender, adding garlic and stirring in eggplant for the last minute. Stir in tomatoes; cook and stir 1 min. Cover; simmer on medium-low heat 10 to 15 min. or until tomatoes are softened and vegetables are tender, stirring occasionally. Stir in basil.