8 tortillas (We love Siete brand or local corn tortillas)
1⁄2 cup (2 ounces) shredded cheese (we used cheddar)
For the chicken and vegetables: In a liquid measuring cup, whisk together the pineapple juice, lime zest, lime juice, olive oil, onion, garlic, chili powder, cumin, oregano, smoked paprika, and 1⁄2 teaspoon of the salt.
Place the chicken in a large bowl and add the marinade, making sure to evenly coat all the pieces. Refrigerate for at least 1 hour or as long as overnight.
Adjust an oven rack in the center and another 4 to 6 inches from the broiler and preheat the oven to 400°F. Spray a large rimmed sheet pan with oil and set aside.
Remove the chicken from the marinade, shaking off any excess, and place it on the prepared pan. Add the bell peppers and onion to the bowl with excess marinade, and toss well. Spread the vegetables evenly on the pan around the chicken and sprinkle with the remaining 1⁄2 teaspoon salt and pepper to taste.
Bake on the center rack until the chicken is almost cooked through, about 15 minutes.
Meanwhile, for the guacamole: Mash the avocado in a small bowl with a fork. Add the lime juice, salt, and cilantro, and stir to combine. Set aside.
Switch the oven to high broil. Give the vegetables and chicken a good toss, move to the top rack, and broil until the vegetables are slightly charred and the chicken is cooked through, 4 to 5 minutes. Remove the pan from the oven and transfer the chicken to a cutting board. Place the tortillas directly on the top oven rack and broil until warm and slightly charred, about 1 minute, or char on an open flame on the stove top. Slice the chicken into smaller pieces and mix with the vegetables.
To assemble, evenly distribute the chicken and vegetables among 8 tortillas. Top with the guacamole and cheese.