Add the chicken, diced tomatoes or salsa, chicken broth, chili powder, smoked paprika, oregano, cumin, and salt to the slow cooker.
Arrange the chicken in a mostly even layer, cover, and cook on High for 4 hours.
Shred the chicken directly in the slow cooker with two forks, stir it into the cooking liquid, cover, and let it rest for 10 minutes.
Taste the shredded chicken and add more salt only if needed.
While the chicken rests, cook the rice and warm the black beans and frozen corn.
Chop the cilantro, dice the avocados, and cut the limes into wedges.
Divide the rice among serving bowls, then add the shredded chicken, corn, black beans, and diced avocado.
Garnish each bowl with cilantro and lime wedges, drizzle with cilantro lime dressing, and serve immediately.