If you already have your nutrition data and just need to create a label, the easiest way to do that is to create a custom ingredient. All labels on ReciPal are based on a "recipe", even if that recipe is just a single ingredient.

Add the nutrition facts you already have for your custom ingredient, add just that custom ingredient to a recipe, and finalize the recipe to create a nutrition label. This way, you treat your product as a single ingredient and your full recipe has just that one ingredient.