Preheat the oven to 400°F. Lightly grease (or line with parchment) a large baking sheet.
1) Whisk together the flour, baking powder, baking soda, salt, cinnamon, and sugar.
2) Work the butter into the dry ingredients till the mixture is unevenly crumbly; don't be afraid to leave some of the butter in pea- or marble-sized chunks.
3) Add the ground pecans and chips, stirring to combine.
4) Dissolve the espresso powder in the hot water.
5) Gently stir the dissolved espresso and sour cream or yogurt into the dough, just till it's well dispersed; the dough will be very crumbly.
6) Add enough ice water to bring the dough together in a cohesive mass.
7) Gather the dough into a ball, and place it on a well-floured work surface.
8) Pat/roll it into an 8" to 9" circle about 3/4" thick.
9) If desired, brush the surface of the dough with milk, and sprinkle with coarse white sparkling sugar.
10) Use a 2" cutter to cut about 20 scones, gathering the scraps and gently shaping into round scones without re-rolling.
11) Place the scones on the prepared baking sheet, leaving just over 1" between them.
12) Bake the scones for about 20 minutes, till they're golden brown. When you break one of the center scones open, the middle should be baked all the way through, not doughy or wet.
13) Remove the scones from the oven, and serve warm.