Preheat oven to 350F and grease a 9x5" loaf pan or two 8x4" loaf pans.
Combine all dry ingredients in a medium bowl. Set aside.
Combine all wet ingredients in a large bowl.
Add dry ingredients to wet ingredients and mix just until incorporated.
Fold in nuts and/or chocolate chips if desired.
Pour batter into prepared pan(s) and bake until a toothpick inserted into the center comes out mostly clean. About 1h 10mins for one 9x5" pan and 50mins for two 8x4" loaf pans.
Cool in pan on a wire rack for 10mins then turn out onto a cooling rack to cool completely.
Store in an airtight container on the counter for 3-4 days. Can be refrigerated or frozen for longer storage.
Notes
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.