The Android OS doesn't yet provide native support for printing, so printing from Google Nexus 7 tablet is not a function delivered. The USB port also not support printer interfaces.
However, with the addition of some Android app, you can easily print from a Nexus 7 over a Wi-Fi network. There are a few apps in Google Play, allowing you to print directly to a Wi-Fi printer, such as Cloud Print, PrinterShare Mobile Print. If you have a printer with a Bluetooth connection, some apps also support Bluetooth printing.