In a medium bowl, whisk together flours, baking soda, ground cinnamon, and salt. Set aside. In a large bowl, beat butter and sugars together until creamy, about 2 minutes. Add egg, banana, and vanilla and beat until combined. Add flour mixture to butter mixture and mix slowly. Add ¾ cup of chopped walnuts and mix until combined.
Using a large cookie scoop or ice cream scoop, scoop the dough and place on a plate or tray. You should get 12 evenly -sized cookies. Cover with plastic wrap and chill until firm, about 4 hours.
Once cookie dough is chilled, preheat oven to 350 degrees. Prepare 2 baking sheets by lining with parchment paper. Set aside.
Place remaining walnuts, and both sizes of chocolate chips in a medium bowl. Toss together until combined. Grab one ball of chilled dough and roll into a smooth ball. Place one side of the dough ball into the chocolate chips and walnuts. Press the chips into the dough to ensure they stick, making sure to cover as much of the top half of dough as possible. Place the dough ball onto a prepared baking sheet, smooth side down. Repeat with the rest of the dough balls, making sure they are at least 3 inches apart from each other on the baking sheet. Place only 6 dough balls on each baking sheet to ensure they don't touch.
Bake cookies in preheated oven for about 16-18 minutes. The edges of the cookie will turn golden brown when they are done. Remove from the oven and let them cool completely before eating. You can eat them warm but they taste much better cooled to room temperature.