Copper Nugget is a mining drop obtained when using a pickaxe less than netherite to mine copper ore. 9 copper nuggets can be crafted into 1 raw copper.
Stone Pickaxe = 1-2 copper nuggets
Gold Pickaxe = 1-5 copper nuggets
Iron Pickaxe = 3-6 copper nuggets
Diamond Pickaxe = 50% chance to drop 5-8 nuggets (otherwise drops raw copper)