There are some new OTA updates rolling out to Nexus devices today, but don't expect any big changes. T-Mobile has posted the update details for Nexus 4, 5, 6, and 7 LTE patches. They're all minor security and bug fix updates, but that's nothing to scoff at.
Like most carriers, T-Mobile will probably have its own variant of the Nexus 6 OTA. In this case it's LYZ28K. Other carriers will have slightly different builds. The updates for the Nexus 4, 5, and 7 should be the same everywhere. Those are all build number LMY48M. Presumably the WiFi Nexus 7 will get the patch as well, but T-Mobile is obviously only confirming the LTE variant.
The OTAs are small this time. The Nexus 6 update is almost 30MB, but the others are under 20MB. They won't take long to download, but they're rolling out in waves. We're not seeing anything on our end yet. Google promised monthly security updates recently, so maybe this is it? No word from Google, but Nexus devices tend to get a lot of patches anyway.
The LTE Nexus 9 is also getting an update according to Tmo. It's LMY48M like the others.