Add chocolate chips to melted butter and melt in microwave in 15 second increments, stirring between each until chocolate is fully melted and smooth (or use a double boiler method on the stove top).
Add Rice Chex to a large bowl and slowly pour the chocolate mixture over the top. Gently stir to fully coat all the cereal in chocolate.
Add 1 cup confectioners sugar, carefully stirring to evenly coat the chocolate cereal.
Sprinkle toffee bits and M&Ms over the top and again stir gently.
Place in an air tight container for up to a week.
Recipe by My Frugal Adventures at https://myfrugaladventures.com/2018/12/chocolate-toffee-muddy-buddies-recipe/