Combine the shredded chicken and mole in a saucepan. Warm over medium-low heat for about 5 minutes. The mixture should be moist but not runny; add a little broth if it seems dry. Set aside to cool.

Wipe the leaves clean with a damp towel and cut them into eight pieces, each approximately 12 inches square. Pass each piece briefly over a low gas flame or warm it in a dry skillet for several seconds per side. This softens the leaves so they can fold without cracking.

Mix the masa harina, baking powder, and salt in a bowl.

In a separate large bowl, beat the lard for 2–3 minutes, until light and creamy. Gradually beat in the masa mixture, alternating with 1 1/2 cups of warm broth. The dough should be soft and spreadable, similar to thick peanut butter. Add more broth, 1 tablespoon at a time, if needed.

Place one banana-leaf square on the work surface. Spread about 1/3 cup masa into a roughly 5-by-4-inch rectangle in the center. Place about 1/4 cup chicken filling down the middle.

Fold the long sides of the leaf over the filling so the masa edges meet and enclose it. Fold the top and bottom toward the center to form a flat rectangular packet. Place seam-side down. Repeat with the remaining ingredients.

Add water to a large steamer pot, keeping the water below the steamer basket. Arrange the tamales seam-side down in the basket. Cover them with leftover banana-leaf pieces or a clean damp kitchen towel, then cover the pot.

Bring the water to a boil, then reduce to a steady simmer. Steam for 60–75 minutes, checking occasionally and adding hot water as needed. The tamales are done when the masa feels firm and pulls away easily from the banana leaf.

Remove the pot from the heat and let the tamales rest, covered, for 10–15 minutes. Serve warm with extra mole sauce, Mexican crema, or pickled onions.