AT&T is on a roll over the past few days. They just started the official rollout of Nougat for the S7 and S7 Edge last week and now the LG G5 is also starting to receive the update. Meanwhile who knows when Verizon devices will start to receive their Nougat updates. My VZW S7 Edge is patiently waiting. To grab the update for your LG G5 head to your system settings and check for updates there. Apparently you will need to be on wifi and can only check once per day.
The Nougat update weighs in at a hefty 1.5GB which could explain AT&T's requirement for being on wifi. This update also features the January 1st security patches and will bring you up to Nougat 7.0. There is still no 7.1.1 for the G5 on AT&T for now. You should start seeing notifications for this update in the coming days as well.