Preheat the oven to 400 degrees F.

Pierce each yam with a fork and lightly coat in oil. Cover in aluminum foil and bake until fork tender, about 30 minutes. Meanwhile, in a medium sized bowl, mix the sour cream, coconut milk, 3/4 cup of coconut, half of the chives and lime juice. Place mixture in refrigerator and chill until ready to use. When yams are cooked through, set aside until cool enough to handle. Remove foil, and cut each yam in half widthwise. Make 2 incisions at the rounded end of the yam to form an 'x' and spread open. Set the yam on its flat side, and top with a dollop of the coconut chive sour cream. Garnish with the remaining coconut and chives.