The Mexico Front of Package regulations were published in 2014 and are mandatory for most pre-packaged foods and non-alcoholic beverages. The regulations are separate from those for the Nutrition Facts panel.
Link to the regulations, including the food reference amounts: http://www.dof.gob.mx/nota_detalle.php?codigo=5340693&fecha=15/04/2014
There are 4 types of labels based on the label and portion size: