In a large bowl, combine rice cereal, oats, ground flax seed, brewers yeast and salt. Stir together then set aside.
In a small saucepan, melt together the almond butter and honey over medium-low heat. Stir together until smooth and evenly combined. Remove from heat and stir in vanilla extract.
Pour the melted honey and almond butter mixture into the large bowl with the dry ingredients. Fold together until evenly combined. Allow to cool for a few minutes before adding chocolate chips (so that they don't melt). Fold in chocolate chips.
Line an 8x8 baking dish with parchment paper. Transfer the mixture from the large bowl to the baking dish. Using a spatula, smooth the mixture down along the edges until the top is evenly flat. Refrigerate for at least 1 hour or up to overnight, until set.
Once they are completely cooled and set, use a sharp knife to cut into bars. Leftovers can be stored in an airtight container (with parchment paper in between to prevent sticking) for up to 4 days at room temperature or up to 3 months frozen.
I recommend freezing the chocolate chips for 10-15 minutes prior to adding to the recipe to help prevent melting since the honey and almond butter will still be slightly warm.