Heat oil in medium skillet on medium-high heat. Add onion and pepper; cook until softened, about 3 minutes. Add garlic; cook and stir 1 minute or until fragrant. Stir in tomatoes, stock, Hot Sauce, lime juice, chipotle peppers, salt, pepper and cumin. Simmer 6 - 8 minutes until slightly thickened. Remove from heat.

Transfer mixture to blender container. Puree on high speed, with center of lid removed to allow steam to escape, until well blended and smooth.

Return sauce mixture to skillet. Add chicken, stirring to coat well with sauce. Cook on medium heat just until heated through. Spoon chicken mixture into tortillas. Serve with assorted toppings, as desired.