All signs point to a new Nexus 5 coming in the near future. We first saw a Google employee holding a new phone with the "Nexus" branding on it during an Android 4.4 KitKat promotional video. Then a couple of devices, the LG D820 and D821, made their way through the FCC. Evleaks, known for accurate reporting on unannounced phones, first said that those devices were probably variants of the already announced LG G2.
Evleaks issued a correction on Wednesday, however, stating that "It looks like I was wrong about the LG D820/D821." That implies, though doesn't confirm, that those devices could still very well be the Nexus 5. A pass through the FCC doesn't mean a definite launch, but it does mean the devices are approved to run on U.S. wireless networks and are safe for consumers.
So now we basically sit back and wait for Google to announce the phone. It's absolutely unclear when Android 4.4 will launch, especially since Android 4.3 Jelly Bean is still just a few months old, though we could see it in time for the holidays.