The kitten of Nordic languages…
Again, of all the Nordic languages, Swedish is the easiest to learn how to speak if you’re a native English speaker. If the difficulty of learning languages were cats, Swedish would be a cute house cat that begs politely for milk. Although Dutch isn’t Nordic, their language is somewhat similar to German and would be a grumpy cat who has no time for shenanigans.
German grammar is like a tiger that hasn’t been fed in a week. Learning German is a punishment in and of itself. As for the Icelandic language, you’d have an easier time traveling across the galaxy and coming across aliens than you would learning their language.