Preheat the oven to 350 degrees F.
For the cilantro-lime cream: In a bowl, combine the sour cream, honey, lime juice, cilantro, coriander, cumin, salt and pepper and whisk together. Refrigerate until using.
For the braised chicken: Heat a saute pan over high heat. Sprinkle the chicken with the kosher salt and pepper. Add the grapeseed oil to the pan and sear the chicken on both sides until golden brown, about 2 minutes per side. Do not overcrowd the pan; sear the chicken in batches if needed. Remove the chicken from the pan and hold in an oven-safe casserole dish for further cooking.
Add the onions and peppers to the saute pan and cook until tender. Add the paprika, smoked paprika and chipotle peppers and saute with the peppers and onions for 1 minute. Add the chicken broth and ketchup, stir and bring to a simmer. Pour the braising liquid over the chicken and cover the casserole dish with foil. Cook in the oven until the chicken is tender and falls apart, 45 minutes.
While the chicken is still hot, shred it and return it to the braising liquid. If you are using it right away, keep the chicken hot in the braising liquid for plating. (If you are refrigerating the chicken to use later, cool it down and store it in the braising liquid. Reheat it as needed for plating.)
For the guacamole: Cut the avocados in half and remove the pits. With a spoon, scoop out the avocado flesh into a bowl. Add the red onions, tomatoes and cilantro and mash the ingredients together. Season with salt and lime juice.
Divide the lettuce among the taco shells. Spoon about 2 ounces of the braised chicken into each shell. Top with guacamole, a tablespoon of cilantro-lime cream and 2 sprigs cilantro.
To fry your own taco shells, use a taco shell basket and fry white corn or flour tortillas in vegetable oil (heated to 350 degrees F) for about 1 minute. Otherwise, heat store-bought taco shells in the oven at 350 degrees F for 3 to 5 minutes.
Recipe courtesy of Robert Irvine