To begin, you'll zest half of one of the limes into a mixing bowl. Juice the lime into the bowl as well.
Add the mayonnaise, a tablespoon of the avocado oil, cumin, garlic powder, onion powder, coconut aminos, and cayenne pepper. Whisk those together until smooth.
Nestle the chicken breasts down into the sauce, turning them over to coat them well.
Cover the bowl with plastic wrap or foil and refrigerate overnight, or at least 8 hours.
When it is time to cook dinner, preheat your oven to 375 degrees.
Heat the remaining tablespoon of avocado oil in a large cast iron skillet (or other oven-safe skillet) over medium-high heat.
Add the chicken to the skillet and sear the meat for about 2-3 minutes on each side, or until they are golden brown.
Slide the skillet into your oven and bake for about 20-25 minutes, or until the temperature on a meat thermometer reads 165 degrees.
Allow the meat to rest a few minutes before serving.
Cut the remaining lime into wedges and serve the chicken with a lime wedge to squeeze over it and garnish with the parsley or cilantro.