Heat oil in a pan, add chopped onions, and sauté until golden. Add ginger-garlic paste and green chilies, cooking for 2-3 minutes.
Add ground chicken, turmeric, cumin powder, garam masala, and salt. Cook on medium heat until the chicken is fully cooked and browned.
Once the chicken is cooked, stir in chopped fresh coriander leaves for added flavor. Let the filling cool.
If using ready-made pastry sheets, cut them into triangles. If making dough, roll it into small balls and shape them into thin circles.
Place a spoonful of the chicken filling in the center of each pastry triangle. Fold and seal the edges by pressing them together.
Heat oil in a deep frying pan over medium heat. Test the oil by dropping a small piece of dough; it should sizzle immediately.
Gently drop the filled samosas into the hot oil and fry until golden and crispy, about 4-5 minutes. Remove and drain on paper towels.