Rim the Glasses (Optional): If you want to add a festive touch, prepare your margarita glasses by rimming them with chocolate shavings, cocoa powder, and sugar. Here's how:
Moisten the rim of the margarita glass with a lime wedge or a wet paper towel.
Combine chocolate shavings, cocoa powder, and sugar on a small plate. Dip the rim of the glass upside down into the mixture, coating it evenly.
Blend the Margarita: In a blender, combine the tequila, chocolate liqueur, lime juice, orange liqueur (if using), agave nectar (if using), and ice cubes. Blend until smooth and frosty.
Pour and Enjoy: Pour the frozen margarita into the prepared glasses (if you rimmed them) and enjoy!