Put the chicken breast chunks in one bowl and the thighs in another. In a small bowl, combine the coriander, cumin, turmeric, cayenne, salt and pepper. Divide between the bowls of chicken and turn the chicken pieces to evenly coat. Let stand for 20 minutes.
In a large, deep skillet, heat 1 tablespoon of the oil over medium-high heat. Add the chicken thigh chunks in a single layer and cook, turning the pieces occasionally, until nice and browned, about 2 minutes. Transfer to a plate. Repeat with another tablespoon oil and the chicken breast chunks, transferring them to another plate. You just want to sear the chicken, not cook it through.
Add another tablespoon of oil to the pan, reduce the heat to medium, and add the onions and chile. Cook, stirring occasionally, until onions are golden and melted, about 7 minutes. Reduce the heat to low and add the stock, stirring in the beautiful browned bits from the bottom of the pan.
Add the garlic, ginger, 1/4 cup of the coconut milk and 1/4 cup of the water. Stir well, bring to a simmer, and return the chicken thighs to the skillet. Cook for 20 minutes, then add the chicken breasts. Cook for 5 minutes, then stir in the remaining coconut milk and water. Cook 5 minutes longer or until stewy.
Top with cashews and cilantro. Serve with plain steamed peas and basmati rice.