Heat oven to 375°F. Line two baking sheets with parchment.
Pulse rolled oats in a food processor to a coarse flour. Set aside.
Beat butter, granulated sugar, and brown sugar until light and fluffy, 2–3 minutes.
Mix in eggs one at a time. Add vanilla and espresso powder; blend until smooth.
Whisk flour, ground oats, baking soda, baking powder, and salt in a bowl.
Add dry ingredients to the butter mixture in two additions. Mix just to combine.
Fold in chocolate chips, grated chocolate, and nuts until evenly distributed.
Scoop 1½-tablespoon portions onto sheets, spacing about 2 inches apart.
Bake 9–11 minutes, rotating once, until edges are golden and centers just set.
Cool 5 minutes on the sheet, then transfer cookies to a rack to finish cooling.