The 86NANO766QA is a 86 inch 4K TV from LG. It was launched in 2022. It features a 10-bit IPS panel.
The maximum resolution it can display is 3840 x 2160 @ 120 Hz with a pixel density of 51 ppi.
Picture Quality
After screen size and resolution, the next important feature of a display is its Color Reproduction, which is defined by its color gamut specification.
LG has not provided a color gamut specification for this TV. But don't worry, we have other means to guess that. Now, since the TV features a big 86 inch screen, it won't come with a cheap panel, so here we can assume its equivalent sRGB coverage to be 90-100% or above. The color quality on this TV will be Lifelike! Meaning it will produce color accurate images by default.
Understanding Color Gamut
Color gamut specification of a display indicates the range of colors that the display can produce.
In other words, this specification tells the ability of a display to produce accurate colors. A panel with low gamut coverage will miss out on some colors (such as deep red), thus producing a "washed out" picture.
It is specified in different units - sRGB,sRGB (standard RGB), NTSC 1953, DCI P3 etc. It is upto the manufacturer which one they choose.
But you don't need to worry about that, below is a chart that will help you choosing a TV with good color accuracy.
Other than color accuracy, the static contrast specification of a TV has equally important role in picture quality.
The importance of static contrast ratio
There are 2 types of contrast specifications for a TV. Static and Dynamic. We are interested in static contrast ratio. Dynamic doesn't matter much.
This specification tells the intensity of black levels. That is, a TV with static contrast ratio less than 1000:1 may produce black images something like this:

Note that, such TVs are likely be prone to backlight bleeds that will rob your experience — as shown below.

Also, a TV with high constrast ratio enables you to see more details. So, resolution and static contrast ratio go hand in hand in a sense.
If given a choice, I will prefer a FHD TV with high contrast ratio over a 4K TV with low contrast ratio.
LG did not list a static contrast ratio specification for this TV. So once again we have to take a guess based on the TV's other specifications. FYI — IPS panels come with a static contrast ratio between 700:1 - 1500:1. As for a 4K TV, we can guess the ratio to be 1200:1 or above.
HDR is also supported on this TV in form of HDR10 Pro and HLG (Hybrid Log Gamma).
Coming to brightness, it can go as bright as 250 nits. The backlight of this TV is powered by Direct LED technology.
Gaming Performance
Now if you are planning to use the TV other than using it as a TV — like as a PC monitor or for gaming purposes, make sure to get a TV with lowest input lag. For gaming however, both the input lag and response time affects the performance.
Unfortunately, LG did not specify the input lag on this unit. But since this is not a cheap TV from LG, we can expect an input lag of less than 20ms.
What is Input Lag and Why it matters ?
This lag is the amount of time at which device inputs changes the content of the TV. Though, this won't matter much if you aren't into competitive/FPS games like call of duty.
Although for better experience, look for a TV that features an input lag and response time of < 20ms.
Dimensions and Ergonomics
The TV measures 86 inches vertically and 75.87 inches horizontally. It is 2.36 inches thick.
It weighs around 45.2 Kgs and 3.7 kgs extra if you include stand. So plan your space accordingly.
Now, speaking of ergonomics — a VESA mount with interface size of 600 x 400 mm is provided for wall-mounting. The unit doesn't come with either Swivel, Tilt or Pivot support.
Hardware and Audio
The TV comes with a Quad Core CPU. However, we could'nt find any specification on the total RAM on this TV.
The UI on this TV is powered by webOS 22 Operating System.
For display connectivity, LG has provided two HDMI 2.0 ports and two HDMI 2.1 ports on this TV.
To connect USB devices, it includes two USB 2.0 ports. Other connectivity ports include — 1x CI+ 2.0, 1x Antenna (RF) (female), 1x Satellite In (F-type female) and 1x Ethernet RJ45.
For connecting to this TV wirelessly, you will have — Wi-Fi (5Ghz + 2.5Ghz), Wifi-Direct, Bluetooth 5.0 and DLNA.
The Audio unit of this TV is powered by 2 x 10W speakers.
In terms of power usage, the TV uses 166 Watts on average and 0.5 Watts on standby.
For powering this unit, you'll need either a 110V or 220V outlet @ 50Hz-60Hz.