1Heat gas or charcoal grill. In small bowl, mix 1 1/2 teaspoons of the chili powder, the cumin, salt and garlic powder. Spray chicken with cooking spray; sprinkle seasoning mixture evenly over both sides of chicken. Set aside.
2Spray sheet of heavy-duty foil with cooking spray; place corn in center of foil. Turn up edges of foil; place on grill over medium heat. Cover grill; cook 10 minutes, stirring once, until corn begins to brown. Remove corn from grill to medium bowl; set aside.
3Place chicken on grill. Cover grill; cook 12 to 15 minutes, turning once, until juice of chicken is clear when center of thickest part is cut (at least 165°F). Remove chicken to plate; cover to keep warm. Add onion, tomatoes, bell pepper, cilantro, lime juice, chile and remaining 1/2 teaspoon chili powder to corn; toss to combine. Serve with chicken.