Place the chorizo in a food processor and process until finely chopped. Heat the oil in a large frying pan over medium high heat. Add the chicken, chorizo, garlic, chile pepper flakes salt and pepper. Cook, breaking up the clumps with a wooden spoon, for about 15 minutes or until chicken is cooked through. Stir in black beans.
Divide the chicken mixture between the tortillas. Top with the avocado, sour cream and cilantro. Serve with lime wedges and chili sauce.