In a couple weeks, I plan on changing the ATF on my '14 QX80 as well. Unfortunately, there is no ATF dipstick tube and have to change ATF fluid via removing the overflow plug.
Unlike the previous gen QX56/Armada/Titan, there are no trans lines running in/out of the bottom of the radiator which is great. There is an ATF warmer mounted on the engine block to help warm up the ATF. Also, the OE ATF cooler mounted in front of the condenser does have a bypass valve. Depending on ATF temp; if the ATF is cold, it stays closed to let the ATF return back to the transmission to get to operating temps much faster. Of course if its hotter than normal operating temps, the bypass valve opens to let the ATF circulate through the cooler.
"I may think I have inalienable rights to be alive and happy but I don't - life is a blessing."
- Terrence McNally