Run a lime wedge along the edge of a glass and dip it in salt (optional.)
Add tequila, verde liqueur, lime juice and agave nectar to a cocktail shaker and fill ¾ full of ice. Place the lid on the shaker and shake for 30 seconds.
Add ice to a rock's or margarita glass and strain cocktail into glass.
Garnish with a lime wedge.
Video
Notes
Ancho Reyes Verde Poblano Chile Liqueur - find this at your local liquor store. It is worth seeking it out. Lime juice - always use fresh squeezed.