Line a large pan with parchment or foil; set aside.
Pop the microwave popcorn according to package instructions. Once popped, remove any unpopped kernels and place the popcorn in a large mixing bowl.
Gently mix in the mini pretzels and Christmas M&Ms with the popcorn until evenly distributed.
In a microwave-safe bowl, combine the white chocolate or candy melts with coconut oil (if using). Microwave in 30-second intervals, stirring between each interval until completely melted and smooth.
Pour the melted chocolate over the popcorn mixture. Use a spatula or wooden spoon to gently stir until all the popcorn is well coated. Taste and add salt if needed, I had to add some salt to mine.
Spread the coated popcorn mixture onto a large baking sheet lined with parchment paper in an even layer.
Quickly sprinkle holiday sprinkles over the top while the chocolate is still wet.
Once chocolate is set, serve immediately or package in festive bags or containers for gifting.