Lay out sheets of parchment paper on 3 large cookies sheets or directly on a flat surface.
In a large bowl, combine the Cheerios, Chex, peanuts, pretzels and M&M's.
Over a double boiler, melt the chocolate and oil, stirring occasionally, until completely smooth. OR, in a microwave safe bowl, melt chocolate and oil on low heat, stirring every 30 seconds until melted.
Pour melted chocolate over Chex mix and stir to coat. Spread mix onto prepared parchment to dry. Break Chex mix into smaller pieces after completely cooled.
Notes
Nutrition information is for 1 quart; total recipe makes 5 quarts.