Sprinkle Season-All on both sides of chicken. Heat 1 tablespoon of the oil in large nonstick skillet on medium heat. Add chicken; cook 5 minutes per side or until cooked through. Remove chicken from skillet; cover with foil to keep warm.
Heat remaining 1 tablespoon oil in skillet. Add asparagus, mushrooms and onion; cook and stir 5 minutes.
Mix cornstarch and thyme in small bowl. Stir in broth and wine. Add to skillet; stirring constantly, cook 2 to 3 minutes or until slightly thickened. Stir in half-and-half. Cook until heated through. Serve over chicken.