Is it possible to install a single instance of sql server on a server with 2 NICS and 2 different subnet?
By default SQL Server will bind listen to all addresses, so it will be visible from all subnets. You can also explicitly configure SQL Server to listen on only one or the other of the NICs, see CREATE/ALTER ENDPOINT. IT can even listen multiple times on each address (see How to: Configure the Database Engine to Listen on Multiple TCP Ports) usually done for affinitizing clients to hard or soft NUMA (see How to: Map TCP/IP Ports to NUMA Nodes).

Long story short: you don't have to do anything.