Add the chicken to a large pot and cover with enough water to fully submerge it plus 1 inch. Bring it to a boil over high heat, reduce the heat to medium, cover, and cook for 15 minutes or until the chicken is fully cooked. Carefully transfer the chicken pieces to a large plate and set aside to cool. Cover the pot to keep the chicken broth hot and set aside for later use.
Heat 4 tablespoons of oil in a large Dutch oven or pot over medium-high heat. Add ½ of the ancho chiles, ½ of the pasilla chiles, and fry for 1 minute until fragrant, stirring frequently to avoid burning them. Shake off any excess oil from the chiles and transfer them to a large heat-safe bowl. Add in the remaining batch of ancho and pasilla chiles, and repeat.
To the same pot, add the almonds, peanuts, and pumpkin seeds. Pan fry for 1 minute until lightly toasted and fragrant. Transfer them to the same large heat-safe bowl.
In the same pot, heat 1 more tablespoon of oil. Add the corn tortilla and lightly fry for 30 seconds on each side. Transfer it to the bowl.
In the same pot, add the white bread and lightly toast for 30 seconds on each side. Transfer it to the bowl.
Heat another ½ tablespoon of oil in the same pot and add the cinnamon stick. Fry for 30 seconds, stirring often, then add in the raisins and continue frying for 2 minutes. Transfer everything to the large bowl.
Heat another ½ tablespoon of oil in the same pot. Add the black peppercorns, coriander seeds, garlic, and cloves, and lightly fry for 1 minute, stirring often. Transfer it to the bowl.
Heat another ½ tablespoon of oil in the same pot and add the onions. Fry for 3 minutes until softened, then transfer them to the large bowl.
Heat another ½ tablespoon of oil in the same pot and add the sesame seeds. Fry for 1 minute until lightly toasted, stirring often, then transfer them to the bowl. Remove the pot from the heat and set aside.
Add 7 cups of the reserved hot chicken broth to the large bowl of fried ingredients. Cover with aluminum foil or plastic wrap and let everything soak for 15 minutes.
Transfer half of the softened ingredients along with half of the liquid to a large blender and blend for 3 to 5 minutes on high until it’s as smooth as possible. Pour the blended mixture through a fine mesh strainer and into the same large Dutch oven or pot used for frying. Repeat with the remaining ingredients and liquid.
Add the Mexican chocolate, chicken bouillon, and salt in the large Dutch oven or pot filled with the strained mole sauce. Heat over medium heat and cook for 8 minutes, until the chocolate has completely melted and the chicken bouillon has fully incorporated into the sauce. Taste and season with additional salt if necessary.
Add in the cooked chicken pieces and cook for 2 more minutes to heat everything through. Serve chicken with a generous helping of mole sauce and garnish with sesame seeds.