Season the chicken breasts with garlic salt and pepper.
Place the chicken on the smoker and smoke for 2 hours.
With 1 hour left of smoke time, cut the pepper into thirds, and put it on the smoker. Spritz the chicken with a spray bottle of water occasionally while smoking and cooking.
After 2 hours, turn the heat up on the smoker to 400 F. Cook the chicken and pepper for 30 minutes.
To make the avocado crema, mash the avocados in a bowl. Stir in the sour cream, minced cilantro, and juice of 1 lime.
Once the chicken and pepper are cooked, chop them into small pieces.
Spread the avocado crema on each tortilla, top with chicken and sliced pepper, and garnish with red onion, additional crema, and more cilantro.