Mix all the marinade ingredients together and place in a zip-lock bag.
Before you put the meat in, reserve a little marinade to use at the end.(about 1/4 a cup)
Then toss in the chicken, bell peppers and onions. Or if you want more marinade for the meat do not include the peppers and onions. Just coat them with some olive oil and salt before griling.
Marinade for at least 4 hours, but longer if possible.
Grill outside on the bbq, or indoors on a skillet (cast iron is best) or grill pan.
Use the reserved marinade to baste meat as you cook.
When everything is cooked slice the meat, peppers and onions into strips
Combine in a bowl and pour in the remaining reserved marinade (do not use the liquid that the chicken was marinading in)
Serve with tortillas.
Notes
If you're not familiar with liquid smoke, you can find it near the bbq sauces in a small bottle.