Place chicken breasts on other cookie sheet; rub 1/8 teaspoon salt into chicken. Stir broccoli and cauliflower; return to oven on lower rack. Place chicken on upper rack. Bake both pans 10 minutes; brush Sriracha mixture on chicken, and stir vegetables. Bake 5 to 10 minutes longer or until juice of chicken is clear when center of thickest part is cut (at least 165°F) and vegetables are tender when pierced with knife.