Toss chicken with seasoning blend. In a large nonstick skillet, heat 1 tablespoon oil over medium-high heat. Add chicken; cook and stir 5-7 minutes or until no longer pink. Remove from pan. In same pan, add remaining oil, pepper and onion; cook and stir 3-4 minutes or until crisp-tender.
Stir in chicken; sprinkle with cheese. Remove from heat; let stand, covered, until cheese is melted.