In a large ziplock bag, combine the chicken, lime juice, lime zest, olive oil, cilantro, garlic, chipotle in adobo sauce, cumin, oregano, and salt.
Marinate in the refrigerator at least an hour to overnight.
Heat the griddle or skillet over high heat.
Add the onion along with the chicken and marinade.
Cook until chicken is done and marinade has reduced.
This will only take about 10 minutes depending if your cooking surface is hot.
Divide the chicken, onions among the tortillas.
Top with avocado, cheese, and salsa.
Tip: Heat the tortillas on the griddle or pan for a minute.
If you are on a low carb Keto diet, you can still make these fabulous chicken fajitas. To make these Steak Fajitas Keto friendly, use a small low carb tortilla and leave off the salsa and maybe even the onion.