Toast the ancho chilis in a dry skillet over medium heat for about 2 minutes until fragrant and slightly blistered. Remove, then soak in hot water for 10 minutes until soft.
While the chilis soak, season the chicken thighs with a pinch of salt and set aside.
Drain the chilis, then blend them with garlic, cumin, cinnamon, cacao nibs, and a splash of chicken broth until smooth and thick.
Heat olive oil in the Instant Pot or a large skillet over medium heat. Add the chicken and brown for 3-4 minutes per side until golden.
Pour the chili-cacao sauce over the browned chicken, ensuring each piece is coated well. Add chicken broth for extra moisture.
Lock the lid and set the Instant Pot to cook on high pressure for 20 minutes. Once done, let the pressure release naturally for 10 minutes, then quick-release remaining pressure.
Open the lid and shred the chicken using two forks. The meat should be tender, absorbing the rich, smoky sauce.
Taste and adjust seasoning if needed—adding more salt or a squeeze of lime for brightness.
Serve the shredded chicken in warm tortillas, topped with salsas, pickled red onions, or your favorite garnishes for a vibrant feast.
Enjoy your Mayan-inspired cacao and chili chicken tacos, savoring the complex layers of smoky, bittersweet flavors.