Mix water and flaxseed together in a bowl; soak 3 to 5 minutes.
Beat coconut oil, white sugar, and brown sugar together with an electric mixer in a large bowl until smooth. Beat the first egg into the butter until completely blended. Add vanilla with the second egg and beat until smooth.
Stir flour, brewer's yeast, and salt together in a separate bowl; add to the large bowl and mix until just incorporated into the coconut oil mixture forming a dough. Fold oats and cocoa nibs into the dough; roll into small balls, arrange onto baking sheets, and flatten slightly.
Bake in preheated oven until lightly browned, 10 to 12 minutes.