Hasta la vista - Literally means "until the view" or "until we see each other again."
Hasta luego - Literally means "until later" or "see you later."
Nos vemos - Literally means "we see each other" or "see you later."
Chau - This is a more informal way to say goodbye. It is commonly used in Argentina and Uruguay.
Chao Pescao - This is also an informal way to say goodbye. It is used in Puerto Rico and the Dominican Republic.
Adios, amigos - This is a more formal way to say goodbye to a group of friends.