Sprinkle onion powder evenly over chicken breast tenders; toss to coat well. Spray nonstick Dutch oven or large saucepan with nonstick cooking spray. Heat over medium-high heat until hot. Add chicken; cook until browned.
Add all remaining ingredients except water and cornstarch. Bring to a boil. Reduce heat to low; cover and simmer 15 minutes or until vegetables are tender and chicken is no longer pink in center.
In small bowl, combine water and cornstarch; blend well. Add to chicken mixture; mix well. Bring to a boil. Cook and stir until thickened. If desired, season with salt and pepper.