Preheat oven to 350 degrees F (175 degrees C). Line 12 muffin cups with paper liners.
Puree bananas and dates in a food processor until smooth. Add almond butter, coconut flour, coconut oil, palm shortening, cocoa powder, baking soda, vanilla extract, and salt. Pulse to make a thick batter, scraping sides to fully incorporate ingredients.
Spoon batter into prepared muffin cups, filling them ⅔ full. Toss chocolate chips and walnuts together in a small bowl, then sprinkle on top of each muffin, pressing them gently into tops.
Bake in the preheated oven until a toothpick inserted into the center of a muffin comes out clean, 16 to 18 minutes.