NEW YORK (Reuters) - Former NFL quarterback Colin Kaepernick, who sparked controversy by kneeling during the national anthem to protest racial injustice, will be the face of a Nike Inc ad campaign for the 30th anniversary of its “Just Do It” motto, according to ESPN on Monday. He stirred national debate by taking a knee while the anthem was played before games during the National Football League’s 2016 season to draw attention to police killings of black men and other issues.