Preheat oven to 350F and grease bottom only of a 9x5" loaf pan.
In a medium bowl, whisk flour, baking soda, and salt to combine. Set aside.
Cream butter and sugar until light and fluffy (2-3mins).
Add eggs one at a time, fully incorporating after each addition. Add in bananas, buttermilk, and vanilla. Beat until smooth.
Add in flour mixture and mix just until incorporated.
Fold in nuts and chocolate chips.
Pour batter into prepared pan and bake until a toothpick inserted into the center comes out mostly clean. Approx 1h 10mins.
Cool in pan on wire rack for 10mins. Loosen the sides of the loaf from the pan, remove, and place onto cooling rack to cool completely.
If you use BOTH 1 cup of chocolate chips and 1/2 cup of walnuts, your 9x5" loaf pan will be quite full. Mine didn't spill over while baking, but it can or create a bit of a lip. So just be wary of that and either bake in a larger loaf pan, or reduce the chocolate chips, or make muffins with the extra batter.