Take heavy bottom fry pan add oil,once heated add Nigella seeds and let it pop uo
Once add potatoes and salt and cook till potatoes are tender
Now add sugar and cook for 1 minutes
In the nean time grind poppy seeds and green chili into fine paste
Add the paste to cooked potatoes and cook till the raw smell of pippy seed goes off
Approx 10 minutes off the gas,and consistency acciring to your personal choice
Serve hot with rice /roti