These tamales have a smoky, chipotle flavor to go with the sweet corn.
Soak corn husks in water for 24 hours.
Preheat oven to 425 degrees. In a heavy skillet over medium-high heat, toast cumin, peppercorns, and oregano, shaking pan often, until aromatic, about 2 minutes. Let cool, and finely grind. Puree spices, garlic, 1 1/2 teaspoons salt, and chipotles in food processor.
Roast chicken for 30 minutes. Remove from oven and brush with spice mixture; roast until juices run clear when chicken is pierced in thigh, 30 minutes more. Let cool.
Meanwhile, heat oil in a large skillet over medium heat. Add onions, 1 teaspoon salt, and pepper; saute, stirring often, until soft and fragrant, 3 to 5 minutes. Add corn and tomatoes; cook until corn is soft and tomatoes start to break down, 3 to 5 minutes. Transfer mixture to a bowl.
Shred chicken meat. Add chicken, stock, 1 1/2 teaspoons salt, and cilantro to onion mixture. Toss well, cover, and refrigerate.
Whisk together masa harina, remaining tablespoon salt, and 6 cups warm water.
Pat husks dry. Set aside 34 of the best husks; peel remaining ones into ribbons to use as ties.
Working with a few husks at a time, spread about 3 tablespoons masa mixture in center of each; mound 2 heaping tablespoons chicken filling on lower third. Fold husks over, enclosing filling; tie ends with husk ribbons.
Place tamales in a steamer basket over boiling water; reduce heat, cover, and steam until masa is cooked and filling is hot, about 45 minutes. Slice open husks, and serve.
In this recipe, corn husks are lined with masa harina, a Mexican corn flour.