In a large bowl, combine almonds, peanuts, walnuts, cereal and flaxseed; set aside.
In a medium saucepan set to medium-high heat, combine honey, corn syrup, salt and vanilla. Stir frequently, until mixture reaches 260 degrees F on a candy thermometer (hard ball stage).
Immediately pour syrup over nut mixture. Stir until all ingredients are well incorporated. Pour mixture into prepared pan and spread evenly. Refrigerate for 20 minutes to harden.
Once hardened, cut into 20 bars. Melt chocolate and oil in your microwave, in 30 second increments, stirring until smooth. Dip and/or drizzle bars with melted chocolate. Refrigerate to let chocolate set.