EMERGING MARKETS-Mexican peso up on NAFTA talks, Trump investigation

SAO PAULO, Nov 17 (Reuters) - The Mexican peso firmed as much as 1 percent on Friday amid expectations that ongoing NAFTA talks in Mexico City would adopt a slightly more deliberative tone than in the past and focus on low-impact issues. The peso, which was trading at its strongest level against the dollar since mid-October, was also lifted by news that U.S. special counsel investigators into possible Russian interference in the 2016 U.S. election were seeking more documents from the Tru