Combine all ingredients in a large bowl. Cover and marinate overnight.
Heat a cast iron skillet over very high heat. Once hot, transfer chicken, peppers, and onions with marinade liquid into the pan.
Let sear for 60 seconds before stirring the chicken and vegetables. Continue to sauté every 30 seconds or so until the chicken is cooked through and the vegetables are tender-crisp (about 4-6 minutes total).
Serve hot in the skillet, with warm tortillas, lime, and cilantro.
Notes
To store Tequila Lime Chicken Fajitas, place leftovers in an airtight container and refrigerate them in your fridge for up to 3 days. You can also freeze them for up to 2 months.To reheat, thaw if frozen, then warm in a large skillet over medium heat until hot, or microwave in 30-second intervals, stirring in between.