Food etc.
The European chain 'Spar' is Nizhny's corner shop of choice, which is lucky as they're everywhere and slightly more useful than the average produkty shop. There's an especially big one ('Eurospar') with a selection of European products on ul. Belinskogo.

Clothes
Aside from the boutique shops along Bol. Pokrovskaya ul., there are also a number of smallish shopping centres around the town centre area. For a wider selection of Western shops, head to 'Fantastika' (from Minin Square: buses 45, 90, marshrutka 2, or any other that advertises 'Fantastika'), a large shopping centre with most of the usual shops and a very large supermarket. Sedmoe Nebo (Seventh Heaven) on the Lower Bank, ul. Beketova, is pretty similar.