--- Quote Start ---
Is it possible to have multiple sopc in the same Quartus project? If so, what are the naming rules?
--- Quote End ---
It is possible - just create two SOPC's and make sure you use different names of the SOPC's components, e.g.
SOPC#1:
sopc1_cpu
sopc1_jtag_uart
sopc1_onchip_memory
SOPC#2:
sopc2_cpu
sopc2_jtag_uart
sopc2_onchip_memory
..pay special attention to the name of the onchip_memory as the name of the generated HEX-file (containing your NIOS app) that should reside in that onchip_memory should match.
I just posted another thread involving multiple SOPCs:
http://www.alteraforum.com/forum/showthread.php?p=119670#post119670