Preheat oven to 250 F. Get a Dutch oven or cast-iron pot with a tight-fitting lid ready. You will cook the chicken in this pot.
Rub chicken thighs, top and bottom, with half of the Taco Temptation spice blend. Heat oil, a little bit at at time, and sauté onions until translucent. Sprinkle 1-2 tsp. of the rub over onions and continue to cook for another two minutes. Remove onions from pan and place in the Dutch oven. Set aside.
Heat more oil in the pan, and working in batches, brown the chicken thighs on both sides until very aromatic and golden brown. Remove thighs and place on top of the onions in the Dutch oven. Add about 1 cup of water to the frying pan to deglaze, scraping up any bits of chicken, onions, and spices. Pour the deglazed pan scrapings, along with the chicken broth and lime juice over the top, cover and bake for 2 ½ hours, or until very tender. Remove from oven and cool enough to handle.
Using two forks, shred the chicken and put the shredded chicken back into the broth that is still in the Dutch oven. Cover and refrigerate until ready to heat and serve.
This step can be done several days ahead of time, and in fact, the chicken is even better if it has a couple of days to sit back in the juices.
When ready to serve, reheat chicken in the Dutch oven at about 300 F for 30 minutes or so. Heat tortillas in the oven, on a cast iron or over the grill. Serve with shredded chicken thighs, grated cheese and garnish with all of the garnishes you love to have with your tacos!