It looks like the Nexus 5 and Nexus 6 on T-Mobile are slated to get an update to Android 5.0.1 Lollipop today, at least that's what T-Mobile seems to think. Support docs for both phones on T-Mobile's website list December 15th (that'd be today) as the roll-out date for the 5.0.1 update.
The update will bring both phones to build number LRX22C, which brings the ground-breaking feature of "software stability improvements" to the table.
If you want to check if your Nexus 5 or 6 has an update available, just open the Settings app, scroll down to About, and the tap on Software Updates. Between Sprint saying that 5.0.1 is coming this morning and T-Mobile now, we'd wager there's a good chance the update's bound to hit. Or somebody's been whispering sweet little lies into the carriers' ears.