By Jim Finkle and Nandita Bose BOSTON/CHICAGO (Reuters) – Home Depot Inc Thursday said some 56 million payment cards were likely compromised in a cyberattack at its stores, suggesting the hacking attack at the home improvement chain was larger than last years unprecedented breach at Target Corp . Home Depot, in providing the first clues to how much the breach would cost, said that so far it has estimated costs of $62 million. But it indicated that costs could reach much higher. …