Preheat your smoker to 225ºF. If your grill has Traeger Super Smoke or a similar function, enable that as well.
While the grill heats up, slice the onions and toss them with the olive oil and a pinch of kosher salt in a large skillet or smoker-safe dish.
Pat the chicken thighs dry before seasoning with the kosher salt, garlic powder, chili powder, coriander, oregano, cinnamon, and black pepper.
Once the chicken is coated in the rub, place the chicken on top of the sliced onions. It's fine if you have to tuck some of the chicken thighs to fit them all in the pan.
Smoke the chicken for 1 hour at 225ºF before adding the non-alcoholic beer or braising liquid. Loosely cover the pan with foil and use a knife or fork to poke a few holes in the top of the foil to vent steam.
Increase the temperature on your smoker to 350ºF and cook for 75-90 minutes or until the chicken easily shreds.
Shred the chicken and stir together with the onion. Cook the shredded chicken and tortillas for 20-30 minutes at 350ºF, leaving the chicken uncovered, before turning the grill down to a keep warm setting (165ºF to 185ºF) and serving. Add the corn tortillas to the grill in the last 5-10 minutes to warm before serving.