In 10-inch skillet, heat oil over medium-high heat until hot. Add chicken; sprinkle with 1/2 teaspoon garlic-pepper blend. Cook 2 to 4 minutes or until browned, stirring frequently.
Add pasta sauce and mushrooms. Bring to a boil. Reduce heat to medium; cook 5 to 7 minutes or until sauce is of desired consistency and chicken is no longer pink in center, stirring occasionally.
Meanwhile, bring water to a boil. Remove from heat. Stir in couscous, 1/2 teaspoon garlic-pepper blend and salt; mix well. Cover; let stand 5 minutes.
Stir mozzarella cheese into chicken mixture. Fluff couscous with fork; stir in Parmesan cheese. Serve chicken mixture over couscous. If desired, sprinkle with additional Parmesan cheese.