In a large bowl, whip heavy cream to medium-soft peaks. Add in the condensed milk and vanilla, and whip until soft peaks form.
Spoon the mixture into frozen treat molds and insert the stick. Freeze until solid, at least 6 hours.
While the ice cream bars set, make the chocolate shell. In a medium bowl, combine chocolate chips and coconut oil. Place the bowl over a pot of simmering water, making sure bowl does not touch the water. Stir often, until the mixture is fully melted and smooth. Pour into a pint-sized mason jar and allow to cool completely. Store at room temperature until ready to use.
Unmold the ice cream bars. If the ice cream begins to melt during the unmolding process, once removed from the molds pop the bars back in the freezer until fully firm.
One-by-one, dip the frozen bars in the cooled melted chocolate and immediately top with chopped nuts or sprinkles. The magic shell will set fairly quickly, so work one bar at a time.
Enjoy immediately or keep frozen until ready to eat.