In a large bowl, combine the oats, flax seeds, raisins, and chocolate chips.
Add the nut butter and maple syrup and stir until a sticky dough forms.
Using damp hands, form small pieces of dough into balls (you can use a large cookie scoop for consistency, if desired). Continue to wet hands as needed as it keeps the dough from sticking to your hands.
Place formed balls onto a cookie sheet lined with parchment paper and place in the refrigerator for 30 minutes.
Remove the peanut butter balls and place in an airtight container. Store in the refrigerator up to a week. Enjoy!