In a food processor, blend Chex cereal into crumbs.

In a medium size bowl, mix together crushed cereal, peanut butter, powdered sugar and vanilla. Mix thoroughly until combined.

Place bowl in freezer for 10-15 minutes.

Remove the peanut butter mixture from the freezer. Scoop peanut butter mixture and roll into one inch size balls.

Place peanut butter balls on a small tray lined with wax paper. 

Place the tray in the freezer while you melt the chocolate.

Place chopped chocolate in a microwavable bowl. Add 1-2 teaspoons of vegetable oil to chocolate and stir to coat. This will help keep the chocolate smooth, and help thin it a little. You may need to add more oil, depending on how thick your chocolate seems once melted.

Microwave on high, stirring every 30 seconds until chocolate can be stirred smooth. Be careful not to overheat the chocolate! You want to have the chips mostly melted, and be able to stir it smooth.

Dip each peanut butter ball into the melted chocolate. (I find this easiest to do by dropping the ball into the chocolate, spooning chocolate over it, and then lifting it out with two forks. Let it drip for a few seconds, then place on tray).

Place back on wax paper lined tray.

Once you have all of the balls dipped, place tray in freezer for about 10 minutes or until chocolate is hardened. (Make sure it's completely hardened!)

Remove from freezer. 

Place 1/2 cup powdered sugar into a shallow, wide bowl. Roll each peanut butter ball into the powdered sugar. Add more powdered sugar to bowl as needed.

Store in airtight container in refrigerator until ready to eat.