Preheat the oven to 350°F (175°C).
In a large bowl, combine the Fritos, Rice Chex cereal, pretzel twists, and mixed nuts; set aside.
In a small saucepan over medium heat, combine the packed light brown sugar, butter, and light corn syrup; stir until melted and bring to a boil.
Once boiling, let the sugar mixture boil for 4 minutes without stirring, then remove from heat.
Pour the hot sugar mixture over the bowl of chips and cereals and stir gently until all pieces are evenly coated.
Spread the coated mix in a single layer on a large roasting pan or baking sheet and bake for 8 minutes; remove, stir, then return to the oven and bake for an additional 8 minutes.
Transfer the hot mix onto wax paper and let cool completely; once cooled, break into large clumps.
When cooled, sprinkle the mini M&M's over the mix so they stick to the clumps.