ATLANTA (AP) — Now that Georgia Republicans have settled on businessman David Perdue as their nominee for the state's open Senate seat, the real battle begins with a marquee match-up in the fall against Democrat Michelle Nunn that could help determine control of the chamber. Along the way, Perdue dispatched three sitting congressmen to claim the nomination as he crafted a singular message of being an outsider with the business sense needed to tackle the nation's fiscal problems. [...] voters decided change was needed and went with the political newcomer, whose cousin is former Georgia Gov.