Put the chicken in a big Ziploc bag.
Combine the lime juice, tequila, garlic, brown sugar and cilantro and whisk until the sugar dissolves.
Pour this Mexican chicken marinade over the chicken in the plastic bag and squeeze out all the air.
Refrigerate the chicken for an hour, turning the bag a few times.
Preheat the broiler to 500 degrees F (260 degrees C).
Arrange the chicken on a foil-lined baking sheet.
Broil for 5 minutes or until the chicken is partially charred.
Turn it over and broil the other side for 5 minutes or until you see some charring.
Turn the heat down to 325 degrees F (160 degrees C) and cook for another 10 minutes or until the juices run clear.