Mix all the spices from the beginning of the recipe in a bowl. Rub the Spices on the chicken breasts. Save an extra spice mix for future recipes. Put the chicken in the fridge for at least 2 hours, up to a day.
Make the salsa: Mix all ingredients in a bowl. Adjust seasonings as needed. Refrigerate until service. To prevent the avocado from discoloring, we recommend making the salsa closer to service time. You can mix all the ingredients except avocado ahead of time, though.
Heat a little avocado oil in a saute pan over high heat. Carefully place the chicken breasts in the oil. Cook about 2 minutes per side to get a good color on them. If the breasts are very thick, you may want to transfer them to a sheet pan and finish in the oven. You want to cook them to an internal temperature of 165 degrees.
When the chicken is cooked through, let it rest a couple minutes. Then, slice it into thin pieces and garnish with Avocado salsa.