As CyanogenMod 7 nightly build is available for download, you can install CM 7 on Nexus S with Android 2.3 Gingerbread. Since it’s not at RC stage, if you install CyanogenMod 7 on Nexus S it might have some bugs but there are none known as for now. Here’s the guide to help you install CM7 on Gingerbread powered Google Nexus S:
How to Install CM7 on Nexus S
Before you Begin:
Step 0: Copy both of downloaded files (CM7 and Google Apps) to the root of your SD Card.
Step 1: Root Nexus S
Step 2: Open Android Market on Nexus S
Step 3: Search for ROM Manager and install it
Step 4: Launch ROM Manager and tap on ClockworkMod Recovery to install it
Step 5: Once ClockworkMod is installed, tap on Flash ROM from SD Card in ROM Manager
Step 6: Scroll down and search for CM7 zip file that you placed on root of your SD Card.
Step 7: Select “Make a backup” and “Wipe Cache” options and tap on OK.
Your Nexus S will now automatically boot in recovery to install the ROM. Once process is finished, your phone will reboot. That’s it!