There are two completely separate Threads at this point.
“Nest Thread” remains proprietary to google/nest.
However, about 3 years ago Nest donated rights to an open source version, now called just Thread and managed by the thread group, of which Samsung was a founding member.
https://www.threadgroup.org/thread-group#OurMembers
So far only chips have been certified, but there are about a dozen different ones, including from ARM, NXP, and SiLabs.
Same frequency as nest thread (but then, so is zigbee), but a different protocol.
Eero and Legrand are supposed to both have projects in the pipeline:
None of this means a SmartThings hub will actually end up using thread for anything, but it’s a separate initiative than the nest communication protocol. 