Place mango stem-side up. Starting near the center of the fruit, cut from top to bottom, keeping knife as close as possible to the pit. Then slice along other side of pit. Repeat with a second mango. Score flesh of each half and cut off cubes. Combine cubes with 3 ripe kiwis, peeled and cut into 1-inch pieces; 1 cup blueberries; and 1 cup raspberries in a large bowl. Stir in 2 tablespoons mango nectar or coconut-flavored rum and 1 tablespoon light-brown sugar. Chill for 2 to 3 hours.