Line two baking sheets with silicone mats or parchment paper. Set aside.
Add the Oreos to a food processor and pulse until the cookies turn into a fine crumb. Transfer the cookie crumbs to a mixing bowl.
Add the pie filling to the food processor and pulse until smooth. Set aside. (You don't need to clean out the bowl before doing this step.)
Combine the cream cheese and Oreo crumbs with a rubber spatula until completely incorporated. Add the pie filling to the bowl and combine until smooth. The mixture will be a bit on the wet side.
Portion 1 tablespoon of the Oreo mixture into the palm of your hand. Use your hands to roll the truffle filling into a ball shape, and then place it onto the prepared baking sheet. Repeat until you have used all the truffle filling. (There should be about 32 truffles.)
Place the baking sheet in the refrigerator for 30 minutes to 1 hour to set up.
Add the chocolate chips and vegetable oil to a microwave-safe bowl. Heat on HIGH for 1 minute. Carefully remove the bowl and stir the chocolate. Heat for 30 seconds, remove the bowl, and stir the chocolate. Repeat until the chocolate is completely melted and then stir in the cinnamon.
Place a truffle into the melted chocolate. Use a fork to help coat the truffle and then lift it out of the chocolate. Tap the handle of the fork on the side of the bowl to help remove any excess chocolate. Place the truffle back onto the baking sheet. Sprinkle with nuts, if desired. Repeat until all the truffles have been coated in chocolate. (see note)
Return the baking sheet to the refrigerator until the chocolate has set, 10 to 15 minutes. Store in the refrigerator in an airtight container until ready to eat.
Notes
If you don't have a food processor, you can seal the Oreos in a large ziploc bag. Then smash the cookies with a rolling pin until they are a fine crumb = no large chunks.
If the chocolate starts to thicken while you're coating the truffles, return the bowl to the microwave and heat in 30-second intervals until melted and smooth again.