In case your site makes use of multi-currency and you have implemented Nosto multi-currency support, you need to enable and adjust multi-currency settings under the admin.
Add the primary currency variation to the input area as you have mapped it to Nosto. Exchange rates is a specific setting, in case your e-commerce platform supports exchange-rate support. Read documentation here. After including primary currency, add all used currencies (currency variations) similarly and adjust display format accordingly.