Cook Knorr® Rice Sides™ - Cheddar Broccoli in 2-quart saucepan according to package directions.
While Rice is cooking, heat oil in large skillet over high heat. Cut chicken into bite-sized pieces and slice red onion, reserving 1 Tbsp. chopped red onion for garnish. Add chicken and sliced onion to skillet and cook 5 minutes, stirring occasionally, until chicken is thoroughly cooked. Remove from skillet.
While chicken is cooking, slice zucchini and squash. Add to same skillet and cook, stirring occasionally, until lightly browned about 3 minutes. Stir in halved grape tomatoes.
Return chicken to skillet and combine with squashes and cooked Rice.