Place the chicken breasts in the bottom of your slow cooker in a single layer. Pour in the salsa, chopped chipotle peppers, taco seasoning, and chicken broth, stirring briefly to coat the chicken.

Cover the slow cooker and cook on LOW for 4 hours, or until the chicken is completely tender and easily falls apart. Remove the chicken to a cutting board and shred it thoroughly using two forks.

Return the shredded chicken to the slow cooker and toss it in the warm, smoky cooking juices. Leave the slow cooker on WARM and let the meat absorb the flavorful sauce for 10 minutes.

Preheat your oven to 400°F (200°C) and arrange the hard taco shells standing up in a 9x13-inch baking dish. Use a slotted spoon to drain excess liquid from the chicken, then spoon the meat evenly into each shell, filling them about halfway.

Top each taco generously with the shredded Mexican cheese blend, ensuring the meat is fully covered. Bake for 10 to 12 minutes, or until the cheese is melted, bubbly, and the shells are deeply golden and crispy.

Remove the baking dish from the oven and let the tacos cool for 2 to 3 minutes before handling. Garnish with freshly chopped cilantro and serve immediately with sour cream, guacamole, or extra salsa on the side!