Dry chicken breasts; pound chicken between two pieces of plastic wrap to an even thickness.
Whisk together egg and milk in a bowl.
Place fine coconut on a plate.
Dip chicken breasts in the egg mixture, then coat with the fine coconut.
Line a cookie sheet with foil and spray generously with vegetable spray, lay coated chicken pieces on it in one layer. Spray coated chicken pieces with vegetable spray. Bake in a 350f degree oven for 20 to 30 minutes, depending on thickness,until no longer pink. After 15 minutes, turn chicken pieces. If the coconut coat has not turned brown, place under broiler for 2 minutes. Remove to a platter and keep warm.
Tropical fruit sauce:.
Spray a non stick fry pan with vegetable spray, add oil and bring to medium heat; add mango, papaya and ginger, sprinkle with salt and pepper, saute for 6 to 8 minutes until softened; reduce heat.
Meanwhile, add cornstarch, if using, and milk to sour cream, whisk until smooth; add to fruit in fry pan and stir to mix well, slowly bring to a simmer, and simmer for 2 or 3 minutes until slightly thickened. Spoon hot sauce over chicken on the platter, sprinkle toastaed shredded coconut over.