Barnes & Noble Inc said on Tuesday it was launching a video streaming and download service this autumn for its Nook eBooks and device business, Reuters reports. Barnes & Noble, the largest U.S. bookstore chain, said its Nook Video service will allow shoppers to buy movies and television shows from HBO, owned by Time Warner Inc; Viacom Inc; Sony Pictures Home Entertainment and Walt Disney Studios. Barnes & Noble’s Nook tablet and e-reader devices have found favor with shoppers, allowing the bookseller to win as much as 30 percent of the eBooks market, according to its own estimates. But the company faces intense competition from Amazon.com Inc, which already offers the Prime Instant Video service and makes the Kindle Fire tablet…