Preheat your oven to 350 degrees F. Line a muffin tin with paper muffin/cupcake liners.
In a large bowl, mix together all of the dry ingredients, except the chocolate chips.
Melt the coconut oil over low heat in a small saucepan. Mash the bananas with the back of a fork, and mix together with the vanilla extract, coconut oil, and almond milk.
Pour the wet ingredients into the bowl of dry ingredients and stir in the chocolate chips by hand, until just combined.
Evenly distribute the mixture amongst eight muffin liners, and gently press the chopped walnuts into the top of each muffin. Bake them for 25-30 minutes, until an inserted toothpick or knife comes out clean. Allow the muffins to cool in their pan for 5 minutes, then transfer to a wire rack. Allow to cool completely before eating - I find the muffin sticks less to the wrapper if you allow it to cool completely!