Line a large cookie sheet with parchment paper and set aside.
In a large bowl combine the Chex cereal, Cheerios, Bugles, and popcorn.
Melt the almond bark (or candy melts) slowly. Use the microwave in short 15–30 second bursts, stirring in between, or melt in a heatproof bowl over a pan of simmering water.
Pour the melted almond bark over the cereal mixture. Gently stir the mixture with a rubber spatula until all the ingredients are evenly coated in the almond bark.
Pour the mixture onto the prepared cookie sheet and spread the mix into an even layer.
Sprinkle on the M&M candies and sprinkles while the candy coating is still wet.
Allow the mix to sit at room temperature for 30 minutes to set. Or for a faster set, chill the mix in the fridge for 10-15 minutes until hardened.
Once the snack mix has hardened, break into chunks and serve. Store leftovers at room temperature in an airtight container. The mix will stay fresh for a week.