Hi Teymur,
Configuring NAT on an Active/Active pair is the same as any other multi-context ASA. The NAT commands are configured per-context, so you'll just want to login to the appropriate context to configure the commands.
In an Active/Active pair, some contexts are Active on one physical unit, while other contexts are Active on the other physical unit, but that's the only difference. You'll want to make sure you always make changes on the Active version of the context.
Hope that helps.
-Mike