(LEAD) N. Korea’s nuke envoy optimistic of six-party talks NEW YORK, March 6 (Yonhap) — North Korea’s chief nuclear envoy arrived in the United States Tuesday, expressing optimism for the long-stalled six-party talks on the communist regime’s nuclear program.’The six-party talks will fare well,’ the North’s vice foreign minister, Ri Yong-ho, told reporters at New
