Preheat the oven to 350°. Line baking sheets with parchment paper.
Combine the flour, cocoa powder, baking powder, baking soda and salt in a small bowl.
Whisk together the eggs, vanilla extract and sour cream in a medium-size bowl.
Combine the butter and sugar in a large mixing bowl and, with an electric mixer, beat on medium speed until well combined.
Add half the egg mixture and beat until just combined.
Add half the flour mixture and beat until just combined.
Repeat with the remaining egg mixture and remaining flour mixture, scraping down the sides of the bowl once or twice as necessary.
Stir in the Andes chips.
Place the bowl in the refrigerator for 30 minutes (or up to 6 hours) to let the dough firm up.
Drop the dough by heaping tablespoonfuls onto the lined baking sheets, leaving about 3 inches between each cookie. (Balls of dough may be placed next to each other on parchment paper-lined baking sheets, frozen, transferred to zipper-lock plastic freezer bags and stored in the freezer for up to 1 month. Frozen cookies may be placed in the oven directly from the freezer and baked as directed.)
Bake the cookies until the tops are cracked and shiny, 10 to 12 minutes (a minute or 2 longer for frozen dough).
Carefully slide the entire parchment sheet with the cookies from the pan to a wire rack and let the cookies cool completely.