Preheat the oven to 350ºF. Line a 13 × 9-inch baking dish with parchment paper, leaving 2 inches of overhang on each side, and coat with cooking spray.
Combine the sweet potatoes, almond butter, coconut oil, egg, and egg yolk in a food processor. Process until very smooth, making sure no chunks of sweet potato remain, about 1 minute.
Scrape down the side of the bowl and add the maple syrup and vanilla. Process until combined, about 30 seconds.
Add the cocoa powder, salt, and baking soda and process until all the dry ingredients are incorporated, about 1 minute more. Fold in 1 cup of the chocolate chips.
Pour the batter into the prepared pan, spread it into an even layer, and sprinkle with the remaining 2 tablespoons chocolate chips. Bake until the top is set and a toothpick inserted into the center comes out with a few moist crumbs, 27 to 30 minutes. Let the brownies cool slightly.
You can substitute 1 cup canned sweet potato puree for the fresh sweet potato.