NEW YORK (AP) — Nik Wallenda's high-wire act in Chicago boosted Discovery Channel's audience on Sunday. But the Nielsen ratings company says viewer interest in his lofty feats fell far short of his "Skywire" stunt over the Grand Canyon last year. Wallenda's Chicago walks aired live Sunday across the U.S. His first walk between skyscrapers was from 8:35 to 8:42 p.m.Read more on NewsOK.com