Bake biscuits according to package directions.

Meanwhile, saute onion in hot oil in a large skillet over medium-high heat 5 minutes or until golden. Add mushrooms and saute 5 minutes or until tender. Stir in chicken and next 4 ingredients; cook, stirring frequently, 5 minutes or until cheese is melted and mixture is thoroughly heated. Stir in peas, and cook 2 minutes. Spoon chicken mixture over hot split biscuits.