These types of information have a special feature, the Android contacts manager retains only one record of these types in an elementary contact.
If your contact corresponds to only a single elementary contact, you will have only one list of nicknames and only one "notes". You can edit, delete, or add them if they do not yet exist.
By cons, if your contact is an aggregation of elementary contacts, you can have a list of nicknames and a "notes" by elementary contact with the same or different content.
The program will consolidate such information, eliminating duplicates if possible, and will present a list of nicknames, and a "notes". You can as previously edit, delete, or add, and then the same information will be stored in all the elementary contacts.