To make the hard taco shells,* preheat the oven to 350°F and place one oven rack in the middle position, with at least 4” of room between that oven rack and any others.
Place the tortillas in the microwave for 30 seconds to make them pliable.
Pull the oven rack out and drape each tortilla over two bars of the rack to make a U-shape taco shell.
Bake for 12-15 minutes, until the tortillas are browned and crispy.
Remove from the oven, and cool on a baking sheet.
To make the chicken filling, in a medium bowl, combine the garlic powder, chili powder, paprika, cumin, dried oregano, sea salt, and ground black pepper.
Toss the chicken pieces in the seasoning mixture until completely coated.
Heat the avocado oil in a large skillet over medium heat.
Add the coated chicken to the skillet in a single layer and cook until golden brown and cooked through, about 8 minutes.
Add pico de gallo, avocado, and one-eighth of the chicken to each taco shell.
Top with sour cream, chopped cilantro, and squeezed lime juice.