Season chicken with salt and pepper. Heat olive oil in a large Dutch oven or skillet over medium-high heat. Brown chicken on both sides for 3–4 minutes per side, then remove and set aside.

Toast ancho, pasilla, and mulato chilies in a dry skillet for 30 seconds until fragrant. Transfer to hot water and soak for 15 minutes until softened.

In the same skillet, toast tortilla pieces, bread, almonds, peanuts, raisins, sesame seeds, cinnamon stick, cloves, cumin, and oregano until lightly browned and aromatic. Remove from heat.

Sauté onion, garlic, and tomatoes until softened, about 5 minutes.

Add softened chilies, toasted ingredients, sautéed vegetables, and 2 cups chicken broth into a blender. Blend until completely smooth.

Pour sauce through a fine mesh strainer back into the pot for a silky texture. Stir in chocolate, brown sugar, and remaining broth. Simmer for 10 minutes.

Return chicken to the sauce, cover, and simmer on low heat for 45–50 minutes until chicken is fully cooked and tender.

Taste and adjust seasoning with salt or sugar if needed.

Serve chicken over rice, spoon extra mole sauce on top, and garnish with sesame seeds. Serve with warm tortillas.