Not that much, but there are some:
- With alerts you can create as many as you like, on one or multiple external accounts. With nudges you can create a maximum of one of each type of nudge.
- As nudges are designed to help you save, included in the notification is a me2me transfer link that makes it lighting fast to transfer money. With alerts, a me2me link will be included, but you'll need to enter the amount you want to move (if you do want to move money), and check the paying and payee accounts.