Shops selling nuts and dried fruits are very popular in Greece. You can find one or more such places in every neighborhood, and several of them are tightly packed in the Central Market of Athens (check the Varvakeios Market article). These stores do not usually sell prepackaged bags of goods but you can choose the quantity you wish to buy, get it weighed, and packed and you are ready to go!
One of my favorites stores of this kind is 1001 Geyseis (1001 Flavors), because not only do they carry a wide range of nuts, spices, and dried fruits but they also keep up with the times and offer many choices for healthy snacks and delicacies, such as rice crackers and vegetable chips, at reasonable prices. I just love the chocolate-covered nuts in 1001 Geyseis! I recently tried the cocoa-covered pecan nuts and hopefully one day I will try all the variety the store has to offer! I discovered that they also carry many kinds of nut butter and paste (I didn’t know that pumpkin seed butter existed, but it is allegedly tasty and nutritious).
Take your time looking and nibbling around the shop as I am convinced that they offer more than 1000 flavors.