In a large bowl, whisk the vinegar, basil, 1 tablespoon of oil, sugar and salt; set aside.

In a non-stick skillet, sauté chicken in remaining oil over medium heat until juices run clear. Add to vinaigrette and do toss to coat.

Place green beans in a steamer basket in a saucepan over 1 in of water. Bring to boil; cover and steam for 5-10 minutes or until crisp-tender. Add to chicken mixture. Add tomatoes and toss to coat. Cover And refrigerate for at least 1 hour.

Toss before serving.