I really enjoy nuts, and I actually take the Viactiv calcium and vitamin chews. I know I should take "better" vitamins and really do try to, but I choke on them. So at least with the Viactiv I know I'm getting *some* vitamins into me each day, and if I also manage to choke down the better ones, so much the better.
Nuts are really healthy, and much better than just about any junk food you might otherwise eat. I'm in fact eating peanuts right now as I type this. That being said, they are a high energy food - even though that energy is primarily fat. Also many people are mildly allergic to nuts - not to the point of breaking out in red rashes, but maybe to the point of bloating or not digesting food well. So that's why many diets advise holding back on nuts at least in the beginning, so your body sheds the majority of the weight before you see how nuts affect you personally.
That all being said, the key to any diet is that you can keep eating that way. If you resort to eating junk food because you have a craving, nuts are WAY better for you than junk food. On the other hand, if you'd be just as happy with celery sticks, broccoli bites and so on, those would be more nutritious and less energy-providing.