Preheat the oven to 350 degrees F. Coat an 8-inch square baking dish with nonstick cooking spray.
Mix together the crushed cookies, melted butter and 1/2 cup of the finely chopped pecans in the prepared baking dish until the ingredients are combined and resemble crumbs. Using your fingers, press the crust to form an even, compact layer. Bake until crisp, 5 to 7 minutes. Set aside to cool.
Using an electric mixer, beat together the cream cheese, confectioners' sugar and vanilla in a bowl until combined. Fold in half of the whipped topping and place the mixture on top of the cooled crust. Spread evenly.
Next, beat together the chocolate pudding mix and milk in a second bowl until you have a thick mixture. Pour it over the cream cheese layer and spread evenly. Top with the remaining whipped topping and spread evenly again. Sprinkle with the mini chocolate chips and remaining 1/4 cup finely chopped pecans. Chill for 1 hour before serving.