Combine the pork, achiote, cumin, oregano, garlic, orange juice, lime juice, and salt. Marinate for at least 30 minutes.
Simmer the pork and marinade in a covered skillet over medium-low heat for 25 to 30 minutes, until the pork is nearly tender. Cool slightly.
Make the masa:
Stir the masa harina and warm stock together. Beat in the lard until the mixture is soft, spreadable, and holds its shape.
Soften the banana leaves over steam or a low flame, then wipe them clean and cut them into roughly 10-inch squares.
Assemble and steam:
Spread about 1/2 cup of masa in the center of each leaf. Add pork, potato, tomato, rice, olives, and raisins.
Fold the leaf around the filling into a neat parcel and tie with kitchen twine. Repeat with the remaining ingredients.
Line a large steamer with extra leaves. Arrange the parcels upright, add boiling water below the rack, cover, and steam for 2 hours. Check the water halfway through.
Rest the nacatamales for 10 minutes, then unwrap and serve hot.
Notes
Keep the steamer at a steady simmer rather than a hard boil so the parcels cook evenly.
A small test patty of masa can be steamed for a few minutes to check seasoning before assembly.