In deep 12-inch skillet, heat oil over medium-high heat. Cook onion and garlic in oil 2 to 3 minutes, stirring occasionally, until onion is soft. Stir in zucchini, chicken, tomato sauce, beans, tomatoes, salt and pepper. Heat to boiling; reduce heat to medium-low. Cover; simmer 5 minutes.
Meanwhile, in medium bowl, mix baking mix, cornmeal, milk and basil just until moistened. Drop dough by 18 rounded tablespoonfuls onto hot chicken mixture. Cover; cook 8 minutes.