Place chicken breast in a gallon size zip top bag. Pound to ½” thin with the smooth side of a meat mallet, or heavy rolling pin.
Roughly chop half of the cilantro. Very finely mince the other half. Set aside.
Add to the bag with the chicken: juice of 1 lime, the garlic, all of the finely minced cilantro, a pinch of salt and pepper, and a splash of oil. Work marinade into chicken. Marinade in the fridge for 1-6 hours.
Make the pico de gallo: Combine the tomatoes, half of the roughly chopped cilantro, juice of ½ the second lime, the yellow onion, jalapeno, and a pinch of salt and pepper in a medium bowl.
Make the slaw: Combine the shredded cabbage, sour cream, half of the roughly chopped cilantro, juice of ½ the second lime, a pinch of salt and pepper.
Remove chicken from the fridge and let it come up to room temperature. Preheat the grill (or indoor cast iron grill pan) to medium. Remove chicken from marinade and gently pat off excess moisture with clean paper towel. Grill for 3-5 min on the first side. Flip and grill for another 3-5 minutes, or until cooked through. An instant read thermometer should read 165℉. Remove chicken and let rest for 10 minutes.
Once rested, chop chicken into small chunks, serve right away with slaw, pico de gallo, and guacamole.