CUT pineapple lengthwise in half. Cut out fruit, then discard core. Cut removed fruit into bite-size pieces; place 1 cup in medium bowl. Add chicken, rice, celery, peppers and onions; mix lightly. Refrigerate remaining pineapple for snacking or another use.
WHISK oil, vinegar, mustard and ginger until blended. Add to chicken mixture; toss to evenly coat. Refrigerate several hours or until chilled. Meanwhile, refrigerate pineapple shells.
STIR nuts into chicken salad before spooning into pineapple shells to serve.