curl --request GET \
  --url https://api.box.com/2.0/metadata_taxonomies/{namespace}/{taxonomy_key}/nodes \
  --header 'Authorization: Bearer <token>'

{
  "limit": 1000,
  "next_marker": "JV9IRGZmieiBasejOG9yDCRNgd2ymoZIbjsxbJMjIs3kioVii",
  "prev_marker": "JV9IRGZmieiBasejOG9yDCRNgd2ymoZIbjsxbJMjIs3kioVih",
  "entries": [
    {
      "id": "14d3d433-c77f-49c5-b146-9dea370f6e32",
      "displayName": "France",
      "level": 2,
      "parentId": "99df4513-7102-4896-8228-94635ee9d330",
      "nodePath": [
        "99df4513-7102-4896-8228-94635ee9d330"
      ],
      "ancestors": [
        {
          "id": "14d3d433-c77f-49c5-b146-9dea370f6e32",
          "displayName": "France",
          "level": 2
        }
      ]
    }
  ]
}