You don't need precise measurements for this recipe - just use equal parts mashed potatoes and stuffing, and add half the amount of shredded turkey.
Nutritional information is hard to estimate since everyone makes their stuffing and potatoes differently.
For an extra tasty twist, try encrusting the balls in seasoned panko and frying them up in a bit of butter and grapeseed oil. Just form the balls at room temperature or warm them up slightly, press panko on, and chill them slightly if they're too soft before frying.