Prep the ingredients per the instructions above.
Heat the oil in a skillet or non-stick pan over medium heat. Add the onions and peppers, and season with salt and pepper. Sauté until onions are translucent and peppers are tender.
Add in the chicken, garlic powder, cumin, and paprika, and season with salt and pepper. Saute until the chicken is nicely browned and fully cooked to an internal temperature of 160°F (71°C) using a thermometer.
In a bowl, mash the avocado with a fork until smooth. Mix in the lemon, and cilantro, and season with salt and pepper to taste.
Heat the taco shells on both sides in a nonstick pan on medium heat to warm them up.
Portion the fajita, and serve with taco shells, sour cream, guacamole and chips, and fruit punch.