Hello Dan
When you have multiple inside subnets that you would like to NAT to an outside interface, you can use object groups to perform NATting. You can do this regardless of whether those inside subnets are connected to physical interfaces or subinterfaces.
An example of such a configuration is the following, assuming your outside IP address is 50.50.50.10:
object-group network all_subnets
network-object 192.168.0.0 255.255.255.0
network-object 10.10.10.32 255.255.255.224
object network PAT_ip
host 50.50.50.10
nat (inside,outside) source dynamic all_subnet PAT_ip
Now in the same scenario, if you are using DHCP for your outside interface, you can replace the destination object of the NAT command from PAT_ip to the keyword interface like so:
nat (inside,outside) source dynamic all_subnet interface
This will cause the ASA to use the IP address assigned to the outside interface as the IP address for translation.
Take a look at this NetworkLessons Note on ASA NAT with multiple inside subnets for more info.
I hope this has been helpful!
Laz