Heat oven to 375°. Spray cookie sheet with cooking spray. In shallow dish or pie pan, mix bread crumbs and dressing mix. Place sour cream in another shallow dish or pie pan.

Dip chicken into sour cream, coating well; roll in bread crumb mixture to coat. Place chicken on cookie sheet. If desired, spray chicken with cooking spray. Discard any remaining bread crumb mixture and sour cream.

Bake uncovered 30 to 35 minutes or until thermometer inserted in center of thickest part of breasts reads 170°.