Preheat oven to 400F. Spray a 12 cup muffin pan with avocado oil.
In a large bowl mix together the Greek yogurt, apple butter, almond milk, mashed bananas, oil, egg, and vanilla extract until smooth and well combined. Stir in oats and allow the mixture to sit for 5 minutes to soften the oats.
After 5 minutes, add in the flour, flaxseed meal, chia seeds, cinnamon, baking soda, and salt. Stir until just combined. Fold in chocolate chips and chopped nuts.
Divide batter evenly in muffin pan. Bake for 7 minutes at 400F, then reduce heat in oven to 350F (do not open the door) and bake for 13-16 minutes more or until tester comes out clean. Allow to cool for 5 minutes in pan before removing and transferring to a wire rack to finish cooling.
