An argument for the voice being Our Wife, goes back to the mystery of Nick sperging out earlier in the stream about ringing a bell which we don’t hear, and it upsetting people.
It could be a bell that wakes up, or alerts her if he needs her to come down the studio room to get him something during a stream, sort of like a silent panic alarm in a store.
He could have hit it accidentally in his drunken stupor, and that would explain us not hearing the bell, and him blabbering about how someone would be annoyed about it, and a woman showing up some time later, possibly her if she had been asleep and woken up by it.
All speculation of course, from the ramblings of a drunken loon.