In a large bowl, combine the all-purpose flour, chopped walnuts, sugar, baking powder, cinnamon, nutmeg, baking soda, and salt. Create a well in the center of the dry ingredients and set aside.
In a separate bowl, whisk together the almond milk, mashed bananas, melted butter, and vanilla extract until smooth. Add the egg and whisk until fully incorporated. Pour this wet mixture into the well of the dry ingredients, and stir gently until just combined.
Heat a lightly greased skillet over medium-high heat. Pour ¼ cup of the batter onto the skillet, tilting the pan to spread the batter evenly. Cook for 3-4 minutes, until bubbles form on the surface and the edges become firm. Flip the pancake and cook for an additional 1-2 minutes, until golden brown on the other side. Repeat this process with the remaining batter.