Coat an 8-inch square baking pan with cooking spray. Line the pan with parchment paper, leaving an overhang on opposite sides to lift the bars out easily afterward. Coat the parchment with cooking spray.
Add the brown sugar, honey, and butter to a small saucepan and set over medium-high heat. Cook, stirring frequently, until the sugar has dissolved. Bring the mixture to a simmer, then reduce the heat to low and continue to cook for 1 more minute.
Turn off the heat under the pan and stir in the vanilla extract.
Mix the oats and rice cereal in a bowl until well combined.
Pour the melted butter mixture over the oats & rice, then stir with a rubber spatula until well combined. All of the dry ingredients should be moistened.
Pour the mixture into the prepared baking pan and spread it out in an even layer, pressing hard until well-compacted, so the bars don't turn out crumbly.
Sprinkle the chocolate chips over the top of the mixture and lightly press them with the spatula so they stick to the granola mixture.
Allow them to sit for at least 2 hours to set, or in the refrigerator for 30 minutes to speed things up.
Use the parchment handles to lift out and cut into bars.
Individually wrap the granola bars with plastic wrap and store them at room temperature.