Place chicken in a large ziptop bag. Add pineapple juice, soy sauce, brown sugar, and ginger. Shake to mix and coat the chicken. Let marinate 30 minutes.
Coat grill grates with oil and heat grill to medium-high heat.
Grill chicken on both sides until cooked through, about 5 minutes per side.
Let chicken cool 10 minutes and then cut into bite-sized pieces.
In a large bowl, stir together mayonnaise, sour cream, lemon juice, curry powder, and ginger.
Fold in chicken, grapes, pineapple, and green onion. (Note: you may want to cut the pineapple into smaller pieces).
Season to taste with salt and pepper.
Sprinkle macadamia nuts and coconut over the top.
For best flavor, refrigerate for at least an hour before serving.