For the slaw: Using a food processor fitted with a shredding attachment, finely shred the cabbage, carrot and fennel. In a medium bowl, combine the carrot, fennel, cabbage, chives, cranberries and chicken.
For the dressing: In a small bowl, whisk together the yogurt, sour cream, lemon zest, lemon juice, maple syrup, salt and pepper until smooth.
Pour the dressing over the cabbage mixture and toss to combine.
Spoon the filling into the endive leaves and serve.