TUCSON, Ariz. — Pima County Sheriff Chris Nanos , who is leading the investigation into the suspected abduction of Nancy Guthrie , told Fox News Digital Friday that the task force handling the case is making progress nearly 100 days after she vanished from her home in the Catalina Foothills. Asked whether investigators are closer to solving the case nearly 100 days in, Nanos replied, “We are.” He nodded, adding that the developments are “really great” as he got into his white Corvette. He did not elaborate. Guthrie is the 84-year-old mother of “Today” show co-host Savannah Guthrie . He declined to answer another question about Mother’s Day, which is Sunday. Late last month, a private forensic lab in Florida sent a  hair sample to the FBI  for more advanced analysis.…