In medium-size bowl, stir together yogurt, sour cream, sugar and nutmeg. Core pears and chop into small pieces; you should have 1-1/2 cups. Stir into yogurt mixture; cover and chill until ready to eat.
Heat oven to 375 degrees F Place cups on baking sheets and heat at 375 degrees F for 3 to 5 minutes. Remove and let cool. To serve, use spoon to fill cups. Can be filled an hour or two ahead and refrigerated.