My mom always kept a heavy, canvas cloth around 12” X 18” in a plastic bag in the freezer (to prevent rancidity between washings [along with her pastry cloth]) for chopping nuts. You place it over your chopping board (or on the counter if your countertop isn’t precious, or your cloth is thick enough) when chopping nuts and it keeps the pieces from flying everywhere. As soon as I moved out to go to college, I got my own because I couldn’t live without it. I thought everyone had one in their freezer until I left home.