Heat 200 grams of jaggery in a thick-bottomed pan over low heat. Stir continuously until the jaggery melts and forms a thick syrup.
To check the consistency of the syrup, drop a small amount into a bowl of cold water. If it forms a hard ball, the syrup is ready. If not, continue heating and checking until the desired consistency is achieved.
Add 250 grams of roasted peanuts or mixed nuts (cashews, almonds, pistachios) to the jaggery syrup and mix well, ensuring that the nuts are evenly coated with the syrup.
Grease a flat surface or a tray with ghee or oil. Pour the jaggery-nut mixture onto the greased surface and spread it evenly using a greased rolling pin or spatula.
Allow the mixture to cool slightly, and then cut it into desired shapes (squares or rectangles) using a sharp knife.
Let the chikki cool completely before removing it from the tray. Store in an airtight container to maintain its crunchiness.