Hi @aero, when using the Function node you would need to keep the n8n data structure in mind. So the JSON data of your first item would be under items[0].json.data....
However, if the data under nodes is all you want, you might want to take a look at the Item Lists node instead. It would allow you to split out data by giving it a field name (like data.data.brandOffer.nodes in your example), so you wouldn’t have to write JavaScript yourself.