Set aside ½ cup of the bacon. Brush another large, rimmed baking sheet with butter. Top with sheet of phyllo and brush phyllo with melted butter. Repeat, using 20 sheets of phyllo and about half of the butter. Spread about ⅔ of the Nutella on top, and then sprinkle with the toasted nuts, cocoa nibs, and remaining bacon. Top with remaining Nutella and set aside.