While the body cannot make Copper or other Elements, it can build some organic chemical compounds. This process is called anabolism. https://en.wikipedia.org/wiki/Anabolism

I think where this is confusing on what are considered nutrients. Some nutrients can be built by the body, while others cannot. Essential Nutrients are those that cannot be built by human bodies. The Wikipedia page for Nutrients is pretty accessible and interesting: https://en.wikipedia.org/wiki/Nutrient