You’ll need to delete and re-add a payee to nickname it.

To add a nickname for a bill payee:

1. Select Move money from the navigation bar
2. Select Pay bills
3. Select the Manage payees tab
4. Select the trashcan icon next to the payee
5. Select Delete to confirm
6. Select Add payee and follow the prompts
7. When you enter the account number, enter the nickname you choose
8. Select Add payee to confirm