Combine the butter, maple syrup, butterscotch chips, peanut butter, and salt in a small saucepan and melt over low heat until everything is melted and combined. Remove from heat and stir in the vanilla.
In a large bowl, combine the chex cereal and chow mein noodles. Pour the maple butter mixture over top and stir to evenly coat everything.
Add in 1/2 cup each of the marshmallows and chocolate candies and stir again to combine.
Line two baking sheets with parchment or wax paper.
Using two large spoons, dollop roughly 1/3 cup dollops of the mixture onto the baking sheets, about 1 inch apart.
Sprinkle each cluster with the remaining mini marshmallows and candy-coated chocolates. Let set at room temperature then enjoy.