SO put your packing peanuts in one of those ubiqituous plastic shopping bags, tie it shut and put THAT on the bottom of the box... FILL it (the bag I mean) over full so they can't move in there...they are Packing peanuts, they don't need room to breath... Tie it shut.
NOW put your item right on top of the bag. put cardboard pieces cut to size all around it...all sides..put loose fill in between the cardboard and the box wall... put another "bag" of peanuts on top of the item. fill the box to the top or over with loose fill ... bump it up and down gently to settle the fill and add more to get it back up to the top... NOW seal it.
No double boxing required cause you just created an "internal double wall" less bubblewrap wasted, no "meandering packing peanuts" and less broken stuff. (we've had 2-3 items broken in the last 5.5 years..)