Add the chicken to large ziploc bag. Set aside. To the bowl of your blender, add the taco seasoning, olive oil, lime juice, cilantro, green chilies, and garlic. Pulse until very, very smooth. Pour the marinade over the chicken and seal tightly. Place it in the refrigerator to marinate for at least 2 hours or up to 12 hours.
Once the chicken has marinated, preheat a large skillet over medium-high heat. Add the chicken to the pan along with ALL of the marinade. Cook the chicken for 12-14 minutes, tossing frequently, until the chicken is completely cooked through. Remove the chicken from the pan and set aside, leaving some of the marinade behind.
To the pan, now add the onion peppers. Cook the veggies until tender, about 10 minutes. Remove the pan from heat and add the chicken back to the pan. Toss the ingredients together and set aside.
In a large cast iron skillet, place a layer of tortilla chips. On top of the chips, layer cheeses and the chicken mixture. Add more cheese on top if desired.
Place the skillet in a preheated broiler for about 3-4 minutes, or until the cheese is melty and bubbly. Remove from heat and serve immediately, topped with guacamole, sour cream, pico de gallo, and chopped cilantro.