Sort the Magic: Separate the Lucky Charms marshmallows from the cereal. Set aside 2 cups of marshmallows and 6 cups of cereal.
Mix It Up: In a large bowl, combine the 6 cups of Lucky Charms cereal (without marshmallows), Rice Chex cereal, and pretzels.
Melt the Magic: In a microwave-safe bowl, melt the candy coating according to the package instructions (usually 1-2 minutes, stirring every 30 seconds until smooth). Be careful not to overheat, as it can burn and thicken too much.
Coat with Sweetness: Pour the melted candy coating over the cereal mixture and toss gently with a large spoon until evenly coated.
Spread the Magic: Lay the mixture in an even layer on parchment paper.
Add the Sparkle: Immediately sprinkle with rainbow jimmies, then top with Trix Minis and the reserved Lucky Charms marshmallows.
Let It Set: Allow the mix to cool completely before breaking it apart into bite-sized pieces.
Store for Snacking: Keep in an airtight container or plastic bag at room temperature for up to two weeks.