Per flow / per-destination is the default. Per-packet load balancing can be configured on a per-input-interface level.
"show ip interface" will show the interface load balancing method.
"show ip load-sharing" in the admin context will show the current chassis behavior.
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_cli_nxos/l3_manage-routes.html#wp1114960
~jerry