The issue with nuts is that they have a lot of calories, so if you are going to add them, keep a careful eye on quantities and if you stop losing think about either cutting out the nuts or cutting calories someplace else.

In general, though, I think adding some fruit (berries are best because they are low in carbs and low on the glycemic index) and nuts for variety is much better than branching out into all the lowcarb "fake" foods. Try to stay with whole foods in as close to their natural state as possible -- salads, veggies, meat, chicken, eggs, fish, some cheese, a little nuts, berries, etc. Many people find that when they start adding bars, shakes, lowcarb ice cream, etc., their weight loss stops.