Nieto signed a minor league deal with the Marlins on Monday, Matt Eddy of Baseball America reports.
Nieto spent all of 2014 in the majors as Chicago's backup catcher, but was then relegated to Double-A for the entirety of 2015. He struggled mightily in the minors this season, slashing .207/.344/.316 and 77 strikeouts in 81 games, so he appears unlikely to serve as anything more than organizational depth with Miami.