Heat oven to 400°F In large skillet, heat oil over medium heat. Cook bell pepper in oil, stirring occasionally, until crisp-tender. Stir in chicken, salsa and water. Cook 1 to 2 minutes, stirring occasionally, until bubbly. Pour into ungreased 1 1/2-quart casserole; set aside.
In small bowl, stir together remaining ingredients and pour over chicken mixture; carefully spread almost to edge of casserole.
Bake uncovered about 30 minutes or until light golden brown.