Add 3 to 4 cups of the chicken broth to a large pot (save the rest for later when you blend the ingredients). Bring it to a boil over medium-high heat, then reduce the heat to low and simmer.
Make sure you use a pot that is large enough to hold all the ingredients since you will add each of the ingredients to the pot after you char them in a skillet.
While the broth is simmering, cut the stems from the chiles and scrape out the seeds. Heat 2 tablespoons of the bacon grease in a heavy-bottomed skillet over medium-high heat. Add the dried chiles, stirring constantly until they get slightly charred and release their fragrance.
Transfer the chiles to the pot of hot broth. Remove the pot from the heat and let the chiles soak in the broth while you prepare the rest of the ingredients.
Melt some more bacon grease in the same skillet. Add the bread and the tortillas and toast them on both sides over medium-high heat. Tear them into pieces and add them to the pot with the broth and chiles. Push them down into the liquid.
Add the tomatoes and tomatillos to the skillet and cook, turning after 4 or 6 minutes until they get soft and have blackened char marks on them. Add them to the pot with the chiles and bread.
Melt some more bacon grease in the skillet over medium heat. Stir in the onion, garlic, and dried cranberries. Cook, stirring frequently until the onions and garlic are golden and the cranberries are soft, about 8 to 10 minutes. Transfer the mixture to the pot with the chiles.
Add some more bacon grease to the skillet. Add the peanuts, almonds, pumpkin seeds, and sesame seeds. Toast the nuts and seeds over medium heat, stirring frequently until they get golden brown and fragrant. The sesame seeds will start to “pop” when they get toasted. Add them to the pot.
Reduce the heat under the skillet to medium-low. Add the spices to the skillet and stir until they are fragrant, about 2 minutes. Transfer the spices to the pot and give the mixture a stir.
Working in batches, transfer the mixture to a blender. Blend until smooth. Add enough additional broth or water to get the blender to puree everything well.
Transfer the puree into a large saucepan over medium heat and add the salt. Bring the mixture to a simmer and add the chopped chocolate, stirring until the chocolate is completely melted.
Simmer the sauce for at least 15 minutes or as long as 1 hour. The longer you simmer the sauce, the deeper the flavors will develop. Make sure you stir the sauce frequently from the bottom so it doesn’t burn on the bottom.
Add additional broth if you want the sauce thinner.
Taste the mixture and season to your liking.