Prepare the filling:.
Place 2 stacks of 3 bricks on grill grate straddling the coals.(Stack bricks so that top brick is 8 to 10 inches above grill grate.).
Spray grill basket with cooking spray.Remove chicken from marinade, and discard marinade.Place chicken, cavity side up, in grill basket.
Lock basket, and place edges of basket on top of bricks, chicken cavity side down.Grill, flipping basket every 5 minutes, for 30 minutes.
Coals will begin to shrink, and chicken will begin to brown.
After 30 minutes, remove one brick from each stack, and place basket back on bricks.Season with a large pinch of salt and then add to the potatoes.. Add the cilantro and chaat masala to the spice to the potato mixture.
Stir with a wooden spoon, making sure to crumble the curry leaves, until everything is incorporated.Season with lime juice and salt to taste.
Form the mixture into four 2-inch balls and arrange them on a plate in a single layer.Cover with a damp cloth and set aside at room temperature..