HEAT oil in large nonstick skillet on medium heat. Add chicken and garlic; cook and stir 4 to 5 min. or until chicken is evenly browned. Add peppers; cook 3 to 4 min. or until chicken is done, stirring frequently.
STIR in pesto and juice from 1 lemon half; top with cheese. Cover; cook on low heat 2 to 3 min. or until cheese is melted. Spoon over pasta.
SERVE with remaining lemon half, cut into wedges.