Add rolled oats and flax seed to food processor and blitz until blended well. Break up the oats so the texture is a nice grain but not a flour.
Add in peanut butter, honey, and vanilla. Blend again until well combined.
Transfer to bowl and stir in chocolate chips, or add chocolate chips and pulse a few times to combine. Transfer bowl or food processor work bowl to fridge and chill 20-30 minutes to make dough easier to roll.
Scoop the mixture into balls and press mixture in firmly. Roll between palms to form rounded balls. You may have to work the dough in your hands if it gets crumbly, but just keep pressing it together to form a solid piece.