Cut up chile peppers; discard stems and seeds. In a small saucepan, combine chile peppers and the 1/4 cup water. Bring to boiling; remove from heat. Let peppers stand for 30 minutes; drain. Set aside. (If using crushed red pepper flakes, omit this step.)

Arrange chicken in a large skillet; add a small amount of water. Sprinkle chicken with salt and black pepper. Bring water to boiling; reduce heat. Cover and simmer about 12 minutes or until chicken is tender and no longer pink.

Meanwhile, for sauce, in a blender or food processor, combine the chile peppers or red pepper flakes, tomato, onion, the 1/3 cup pumpkin seeds or almonds, the chicken broth, garlic, sugar, the 1/2 teaspoon salt, the coriander, and cinnamon. Cover and blend or process until nearly smooth, scraping down side of container as needed. Transfer to a small saucepan; bring to boiling over medium heat. Remove from heat.

To serve, spoon the sauce over the chicken. If desired, sprinkle with additional pumpkin seeds or almonds. If desired, serve with warmed flour tortillas and lime wedges. Makes 6 (1 chicken breast half and 1/3 cup mole) servings.