Preheat oven to 425F. Line two baking sheets with parchment paper and set aside.
In a large bowl, combine flour, baking powder, baking soda, nutmeg, salt, sugar, and orange zest. Using a pastry cutter or a fork, cut in cold butter until mixture is crumbly.
In a separate bowl, whisk sour cream, eggs, half-and-half, and vanilla until smooth. Pour over dry ingredients, add white chocolate and cranberries and gently stir until a shaggy mass of dough forms.
Turn dough onto a lightly floured surface and gently knead several times until dough just comes together. Divide dough in half and pat each half into a 9-in round. Cut each round into eight wedges and place wedges on prepared baking sheets.
Bake scones at 425F 12-15 minutes or until tops are golden-brown. Cool scones on a wire cooling rack several minutes and serve warm.