Second, I would argue that there is no good snack. Ideally, one should be eating two or three solid meals a day, and nothing between. A few nuts as a condiment for one of these meals shouldn't be problematic - given that you are being somewhat conscious about your omega ratio, taking fish oil, etc - however, the nutritional value of nuts and seeds is arguable.
A lot of them also contain phytic acid, the same anti-nutrient found in grains and legumes that will inhibit mineral absorption. There are much better sources of both fat and protein, in my opinion. If you enjoy nuts: as I said above, you can consciously enjoy them in the correct context. But be aware of what they contain, and which are better/worse. Personally I wouldn't eat walnuts, but I will have macs or almonds from time to time, maybe once or twice a month.