Soak the lentils and fenugreek seeds in sufficient water overnight. Grind with required quantity of water into a smooth paste. Mix with the oats, salt and some water into a batter. Keep aside for an hour. Add some more water if needed.
For the stuffing - Heat 1 tbsp. oil in a pan and temper with cumin seeds. Saute for a few seconds. Add the onion, ginger-garlic, green chilies and curry leaves. Saute till light brown.
Add the boiled chicken ad all the dry spices. Stir fry for 1-2 minutes. Switch off the flame. Add the coriander leaves and lime juice. Toss well and keep aside.
Heat a non-stick pan and brush with some oil. Pour a ladleful of the dosa batter and spread it into a circle. Drizzle some oil around the edges.
Cook on a low flame till one side is done, before flipping it over to cook the other side. Transfer to a plate. Make similar dosas with the remaining batter.
To assemble - Take one dosa and spread some of the chicken stuffing in the centre, lengthwise. Roll it and slice into half. Serve with sambar and coconut chutney.