Preheat the oven to 325 degrees Fahrenheit. Spread oats on a baking sheet and toast for 2-3 minutes. This step is optional.

Line a 9-inch square dish with parchment paper and set aside.

In a large bowl, combine toasted oats, puffed rice, and nuts.

Place peanut butter and honey in a glass bowl. Microwave for 30 seconds to soften them for easier mixing.

Add cinnamon and mix until well combined.

Pour the cinnamon peanut butter mixture over the dry ingredients. Stir until combined and fold in peanut butter chips if desired.

Press the mixture firmly into the prepared pan. Refrigerate for at least one hour or overnight for best results.

Lift the bars out of the pan using the parchment paper. Cut into bars and store in an airtight container for up to 5 days.