Preheat oven to 375 degrees. This is a very heavy dough and mixes best in a stand-mixer.
Grate the 4 oz. chocolate bar over a large plate. The grated chocolate is light and tends to scatter so use something like a pie plate that has sides to it. Set aside.
In a food processor grind the oatmeal to a medium to fine grind, then pour the oats into a medium-sized bowl and add the flour, baking soda, baking powder, and salt. Set aside.
Cream the softened butter and the white and brown sugars together over medium speed until smooth and creamy
Add the eggs and vanilla and beat until combined, scraping the bowl and remixing until you have a smooth mixture.
Add in the oatmeal flour mixture along with the grated chocolate, chocolate chips, cacao nibs, and pecans. Beat on a low speed to slowly incorporate all the ingredients.
Scoop out the cookie dough with a cookie scoop of a tablespoon on parchment-lined baking sheets and bake for 10 minutes until the cookies are golden brown
Let the cookies cool on the baking sheet for about 5 minutes then remove to a cooling rack until cool. Store in an airtight container for several days.
Notes
This cookie batter is very thick, so it is best to use a stand-mixer.