Create Your Base: Mash bananas until completely smooth in a large mixing bowl.
Mix the Protein Magic: Whisk together mashed bananas, protein powder, Greek yogurt, almond milk, peanut butter, and honey (if using) until smooth and creamy.
Fold in the Good Stuff: Gently fold in chocolate chips and chopped walnuts. Don't overmix.
Freeze: Pour mixture into Ninja Creami pint container and freeze for at least 24 hours.
Creami Time: Run through "Ice Cream" setting on Ninja Creami. If crumbly, add 1 tablespoon almond milk and use "Re-spin" setting.