2Place chicken breast one at a time between 2 pieces of plastic wrap smooth side up. Gently pound chicken flat to an even thickness. Use a flat sided meat mallet.Heat oil and then add onion rings stir to keep from burning. when onion is soft remove to plate.
3Season chicken with salt and pepper.
Brown chicken in oil, till golden brown on both sides.Place onions on top of chicken and add margarita mix reduce heat cover and simmer for about 5-10 minutes. Check chicken if there is just a hint of pink remove it to a serving platter along with the onions and cover with foil. You don't want to overcook the chicken. The heat in the chicken will continue to cook the chicken. Turn heat up and reduce sauce to a pancake syrup consistency. Pour Sauce over chicken and serve.
4Note :You can add Tequila when you add the margarita mix but do it off the heat take care as the alcohol fume can ignite. Return to heat and leave the cover off for a few minutes so alcohol can evaporate. Then cover and continue cooking chicken.