Yes, you would need to go through security check and immigration at Narita. I don't think there is a special lane for domestic connections, just the regular, but it has been a while since I did it with ANA. There is Star Alliance Gold Track in Narita, and that is usually quick. Exit passport control is also quick these days, with facial recognition, I can't remember ever seeing waiting time after that came in to play.

With ANA, I'd say an hour would be comfortable, as boarding only starts 30 minutes or less before departure, but with United, and boarding being somewhat longer, you'll probably not get to board with the first groups of you have access to that. But you should be fine to make a 1 hour connection.

They will rebook you to something else if you miss it.