Both SAS and Braathens (today under the umbrella of SAS Norway) have named their aircraft.
SAS named their aircraft with a first name and the last name Viking - here is Steinar Viking (LN-RRA) and where the name is placed.
Up until the last decade or so only male first names were used, but now you will also find female name in the fleet, like the latest 737 addition LN-KKB Cecilia Viking.
Braathens named originally their aircraft after viking kings that had lived around 1000 year ago, like Harald Hårfagre (you probably know him as Harold Fairhair). You will find these viking king names on 737-505s and 737-405s. With the new -705s the names of viking queens were used.
Kurt