NEW YORK--(BUSINESS WIRE)--As part of its ongoing surveillance, Fitch Ratings affirms one outstanding class of the Nissan Auto Receivables 2011-B Owner Trust at 'AAAsf'. A full list of rating action follows at the end of this press release. KEY RATING DRIVERS The rating affirmation is based on available credit enhancement and loss performance. The collateral pool continues to perform within Fitch's expectations. Based on the current structure and credit enhancement, the securities are able to w