Does the CC BY-SA license prevent additional restrictions being placed on derivatives?
I'm wondering, if I release a work under BY-SA, can someone else create a derivative and license it under BY-NC-SA?
No, it’s not allowed.
It says on the license summary page:
No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
And in the license:
For Licensed Material (i.e., the unmodified work):
No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.
For Adapted Material (i.e., a modified work):
You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, Adapted Material that restrict exercise of the rights granted under the Adapter's License You apply.
Creative Commons lists compatible licenses for CC BY-SA and CC BY-NC-SA. If it were allowed, it would be listed there.