Place 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.