Place the butter and sugar on the bottom of a slow cooker.
Pour in the frozen meatballs.
Top with chili sauce and cranberry sauce.
Squeeze in the orange juice from the orange.
Top with orange zest.
Stir after 2 hours to make sure the sauce is well mixed.
Enjoy after the meatballs are heated throughout, approximately 4 hours on low and 2 hours on high.