Preheat grill to medium-high (350°F to 450°F). Coat grill grate with cooking spray. Rub chicken with adobo sauce; sprinkle with 1/2 teaspoon salt and 1/2 teaspoon pepper. Arrange chicken on grill grate; cook 5 minutes on each side or until done. Place 1 tablespoon water and sweet potato slices in a microwave-safe bowl; cover with plastic wrap. Microwave at HIGH 5 minutes or until almost tender. Pat potato slices dry; coat with cooking spray. Arrange on grill; cook 3 to 5 minutes or until tender and grill marks appear. Remove from grill; cut into 1/2-inch pieces. Combine remaining 1/4 teaspoon salt, remaining 1/4 teaspoon pepper, chickpeas, green onions, oil, juice, and basil, if using, in a large bowl. Add sweet potato; toss. Serve with chicken.