If you want to retrieve a list of items by their NDB number (an id assigned by the USDA). Then you can send Nutritionix a filter to get all its sizes. "remote_db_id":3 tells us to filter by our USDA database and "remote_db_key":11143 tells us to filter by the NDB number.
curl -XPOST https://api.nutritionix.com/v1_1/search -d'
{
"appId":"YOUR_APP_ID",
"appKey":"YOUR_APP_KEY",