Spread rimmed cookie sheet or broiler pan with cereals.
Top with peanuts, cashews and bugles and sprinkle seasoned salt lightly overall.
Mix Worcestershire sauce and olive oil briskly to combine
Pour over cereal and nuts. Stir gently until mix is coated. If it seems too dry mix a little more oil and Worcestershire together and add until mixture seems well coated but not too wet.
Bake at 275 for 15 minutes, stir well and return to oven for 15 more minutes. If you are making a really big batch in a deeper pan, increase times to 18-20 min.
After baking immediately spread mix on paper towel lined counter until cool. Toss in M&Ms. I used about 1/2 a large bag. Store in a large tupperware container or ziplock bag.
Keyword chex mix, Christmas party food, M & Ms, snack mix