Line an 8 x 8-inch baking dish with parchment paper. Set aside.
Pour rice cereal into a large bowl and set aside.
Combine the brown rice syrup and brown sugar in a saucepan over medium heat, stirring well. It will be thick like paste, but turns to liquid as it warms. Cook until bubbly, about 2-3 minutes, stirring often with a spatula, then remove from heat. Immediately add ¾ cup peanut butter, cocoa powder, and vanilla extract. Stir until well combined.
Pour the mixture over the rice cereal and gently fold together using a spatula until it’s well-coated. The mixture will be thick and may seem like it won't cover the cereal, but keep stirring, it will be enough.
Transfer the cereal mixture to your prepared pan. Press it down firmly into an even layer using a spatula.
Add the chocolate chips and ½ cup of peanut butter to a microwave-safe bowl. Microwave on 50% power in 30-second increments until melted and smooth. Stir each time.
Pour it over the cereal mixture and spread it into an even layer. Tap the pan a few times to even out the chocolate coating. Sprinkle with peanuts and chocolate chips to decorate if preferred. Place the pan in the refrigerator to cool for 30-60 minutes until the chocolate is set.
To cut, pull up each side of the parchment paper and place on a cutting board. Cut into squares. Store in an airtight container at room temp for 5-7 days. You can also freeze them for 2-3 months.