After T-Mobile tipped us off that Android 4.4.3 wold be arriving today, Google has just released the new factory images for the Nexus 4 (build KTU84L), Nexus 5 (build KTU84M), Nexus 7 (2013 + 2012), and Nexus 10 on their images and binaries download page. You can either sit tight and wait for the update to hit your device over the air, or download and apply via fastboot if you have knowledge in that sorta stuff. Have at it!
[Google factory images | Drivers | AOSP]