In a slow cooker or large pot, place the chicken breasts and pour the chicken broth over them.
In a small bowl, combine chili powder, ground cumin, smoked paprika, garlic powder, onion powder, dried oregano, cayenne pepper, salt, and black pepper.
Sprinkle the spice mixture evenly over the chicken breasts.
Cover and cook on low for 6-7 hours or on high for 3-4 hours until the chicken is cooked through and tender.
Remove the chicken from the slow cooker or pot and shred it using two forks.
Return the shredded chicken to the cooking liquid and stir to combine, allowing it to soak up the flavors.
Let the chicken cool completely, then portion into freezer-safe bags or containers, removing as much air as possible before sealing.
Label and freeze for up to 3 months.
To prepare tacos from frozen chicken, thaw overnight in the refrigerator or reheat directly in a skillet over medium heat until warmed through.
Warm the tortillas in a dry skillet or microwave.
Assemble tacos by dividing the shredded chicken evenly among the tortillas.
Top each taco with shredded cheddar cheese, lettuce, diced tomatoes, chopped cilantro, and a dollop of sour cream.
Serve with lime wedges for squeezing over the top.