So, do you really need lessons? Cross country skiing is different from downhill skiing in the fact that unless you're back country skiing, you won't face steep hills that can be dangerous. While some cross country skiers just take a few lessons to get the basics, others choose to take more lessons and improve their technique. It's up to you to decide what kind of cross country skier you want to be.
Don't know how to decide? Take another look at the issue. If you just want to learn the essentials and know how to maneuver yourself along the trails, you may not want to invest in multiple lessons. However, if you want to become an expert cross country skiers who knows advanced techniques, lessons are probably a good idea. After all, lessons are beneficial and they will make progress come much faster and much easier.
Basically, as long as you take a beginner's lesson to know the basics, lessons aren't mandatory for cross country skiing. However, if you want to progress faster and become a skilled nordic skier, lessons are always a good idea.