Hi @iyinoluwaayoola,
We wanted to mimic the behaviour of Update Mutations when the node exists in case of Upsert . It is not possible to update nested nodes but it is possible to add new nested nodes (just like Update does).
Yes, this is true. We would also be adding support for nested level upserts as well at a later time. We plan to have an upsert variable at each nested level to allow this to happen. This will also offer more flexibility to Users.