Heat oil in medium skillet over medium-high heat until hot. Add chicken; cook and stir until browned.
In 4 to 6-quart slow cooker, combine chicken, celery, carrots, mushrooms, soup mix and water; mix well.
Cover; cook on low setting for 7 to 9 hours.
Separate dough into 5 biscuits; cut each into 8 wedges. Sprinkle wedges with cornmeal. Stir coated biscuits pieces into hot chicken mixture.
Cover; cook on high setting for an additional 25 to 30 minutes or until biscuits are no longer doughy in center.
About 10 minutes before serving, microwave peas in covered microwave-safe dish on HIGH for 3 to 4 minutes or until hot. Just before serving, stir peas and pepper into chicken mixture.