Heat a large skillet over medium-high heat. Add the chicken pieces and season with salt and pepper. Cook until golden brown, about 6 minutes per side. Transfer the chicken to a paper-towel-lined plate and set aside.
In a blender, combine the peppercorns, salt, cloves, cinnamon stick, anise seeds, sesame seeds, pumpkin seeds, raisins, almonds, and coriander seeds. Grind them together into a paste.
Heat the oil in a large pot over medium heat. Add the ground spice mixture and cook until fragrant, about 1 minute. Add the guajillo peppers, ancho peppers, and torn tortillas and cook until lightly toasted about 5 minutes.
Add the chicken pieces and 2 cups of water. Simmer over medium-low heat until the chicken is cooked through, about 45 minutes.
Remove the pot from the heat and add the Mexican chocolate and sugar. Stir until combined. Allow to cool slightly before blending in a blender until smooth.Return the chicken mole sauce to the pot and simmer over low heat for 10 minutes, stirring occasionally. Serve warm with rice or your favorite side dishes.