By Nathan Layne, Tim Reid and James Oliphant NASHUA, New Hampshire (Reuters) – Donald Trump’s commanding victory in Iowa underscores his enduring appeal to a wide swath of Republican voters, and his campaign’s sophisticated, data-driven ground game. But the next nominating contest in New Hampshire will test whether he can replicate that success in a less conservative state. While Trump remains the prohibitive favorite to secure the Republican Party’s presidential nomination, he needs a convincing win in New Hampshire to ensure his surviving rivals have little to no path left to outmaneuver him…