Add coriander powder, paprika, turmeric, garam masala, red chili powder, and salt, and cook for 2 minutes.
In a large vessel, spread out half of the boiled rice, followed by the chicken and potato mixture (masala). Cover with remaining rice. Sprinkle mace and nutmeg over the top, followed by a pinch of food color, if desired. Sprinkle prepared fried onions. Cover and seal the vessel with a cotton tea towel or aluminum foil, followed by the lid. Cook over low heat until the rice has finished cooking, about 45 to 60 minutes.
Measurements are in actual measuring spoons/cups and not eating utensils.
The chillies I use are very spicy. Feel free to increase the red chili powder or green chilies if your chilies are more mild.