Combine Chex and Fritos on a large rimmed baking sheet.
Melt butter and mix in brown sugar, stirring to incorporate and melt the sugar.
Pour butter mixture over all and stir to coat all pieces. Bake at 250 for 15 minutes.
Remove from oven and stir. Return to oven for 15 minutes.
Remove from oven and immediately sprinkle with chocolate and butterscotch chips. Stir, letting the chips melt.
Once the candy chips have melted add the pecans and toss to distribute. Chill.
When chocolate has set up transfer mix to a large ziplock or sealed container. Sprinkle with powdered sugar, about 1/2 cup. Shake or stir until all the mix is coated, adding more sugar if necessary. Makes 1 large ziplock bag full, about 8 cups.
Keyword candy snack, chex mix, party mix, snack mix, Tex-Mex