Grease 9x 13 pan.Layer 1/2 jar peanuts. Melt butter and peanut butter chíps in Microwave. Add sweetened condensed milk, mix and microwave 1-1/2 min. Stir until you can add marshmallows without them melting. Layer onto peanuts. Press mixture down and top with rest of peanuts. Keep in refrigerator and cut into bars.