Heat 1 tsp. oil and saute the ingredients (from coriander seeds to garlic cloves). Cool and grind to a fine paste with some water. Marinate the chicken with this paste for 2 hours.
Heat the renmaining oil and fry the onions till light brown. Then add the marinated chicken, nutmeg, turmeric powder and salt. Saute on low flame till the moisture dries up.
Add 1 cup water and cook, covered till you get the desired consistency.
Add the potatoes and tamarind paste and cook further, covered for 3-4 minutes. Serve hot with rice.