Set oven rack in the lower third of the oven and preheat oven to 350°F.
Toast nuts while preheating the oven.
Lightly grease a 9" x 5" inch loaf pan or 2 smaller loaf pans.
In a bowl, combine flour, cinnamon, nutmeg, baking powder, baking soda, and salt. Whisk well then stir in nuts; set aside.
In a large mixing bowl, whisk the eggs. Add sour cream, vanilla, and oil; whisk to combine. Add the brown sugar; stir to combine. Add the mashed bananas; stir to combine.
Pour the flour mixture into the banana mixture. Mix gently until the dry ingredients are incorporated with the wet and the flour is no longer visible. Do this gently and DO NOT over mix. Batter will be lumpy.
Pour batter into prepared pan(s). Bake 1 large loaf for 60 to 65 minutes and check for doneness @ 45 minutes. Bake 2 small loaves for 40-45 minutes. Test with a toothpick.
Let bread cool in the pan(s) for 10 minutes, then turn out onto a wire rack to completely cool.