You'll notice the model number shows "Full JellyBean on Mako." Historically Google has used code names relating to fish for their flagship phones which further lends credence to the images.
Here are the specs based on what has leaked so far:
Release Date: November
CPU/GPU: Quad-core Snapdragon S4 Pro/Adreno 320
Screen: 4.7" IPS+ LCD (RGB) 1280x768p
Memory: 2GB RAM
Pros: Top CPU/GPU available. Flagship specs across the board including ram, camera, and screen. Nexus phone means non-encrypted boot loader and stock Android. Nexus phones get updates as soon as they are available (unless you're on Verizon).
Cons: No SD card slot. Internal battery. Storage options are limited.
Outlook: The LG Optimus Nexus brings top notch specs, a non-encrypted boot loader and stock Android together in a tidy black package.
Similar phones to consider:
AT&T: Apple iPhone 5, HTC 8X, HTC One X, HTC One X+, Nokia Lumia 920, Samsung Ativ S, Samsung Galaxy S III
Sprint: Apple iPhone 5, Samsung Galaxy S III
T-Mobile: Samsung Ativ S, Samsung Galaxy S III
Verizon: Apple iPhone 5, HTC Droid Incredible X, Motorola Droid Razr MAXX HD, Samsung Ativ S, Samsung Galaxy S III
So, is everyone ready for an LG Nexus phone?
UPDATED - More pictures of the LG Optimus Nexus:
Final case design?