Do I need instruction on how to Nordic Walk? Yes!
Can I learn how to Nordic Walk by myself? Yes!
How is this so...
Although Nordic Walking is a natural movement it requires learning and practice. While it is easier to learn a new movement with a skilled person who can show you how it's done and who can give you useful advice and tips (obviously this is not specific to Nordic Walking) it is not essential. Especially in the age of advanced technology interested people can obtain lots of information about how to Nordic Walk from the internet, anything from pictures, step by step directions articles and videos are available. For example just look at this blog or at the NW Video Channel.
Teaching oneself is definitely possible with all these devices and you're unlikely to put yourself at risk of injury by performing this activity incorrectly; however you're also unlikely to gain much benefit from it if you haven't been able to teach yourself correctly.
Receiving tuition from a qualified instructor makes it much easier to get equipped with the tools you need to not just to perform a proper Nordic Walking technique but also to have the reassurance that you are actually reaping the rewards. An instructor for example can observe your wakling and poling action and advise on what you're doing right/ wrong and where you can improve. And quite often a wrong arm movement is only the result of an improper leg action (eg. your pole plant being too far behind might be the result of a very short stride).
I therefore recommend to have at least one session with a qualified instructor. He / she will show you the steps towards a good basic technique and will assist you in getting there. Once you use the poles in an alternate way (ie. your left leg is in front, your right arm is front - and vice versa) and you plant your poles diagonally backwards you're halfway there. From then onwards you will hardly do anything wrong - however you can still improve your technique to (you guessed it) get even more benefit out of it.
If you decide to enlist the services of a qualified instructor look for an instructor in your area .