As far as the Nexus commercial: I used to have I think an issue of the New Mutants where during a fight someone tries to "read" Ilyana Rasputin and announces they can't because she's a nexus of all probabilities. Don't quote me on that, but I can remember the panel: whomever it is that said it is blind, yellow skin, with a light blue one-piece and cape. I'm thinking #33, 40, 44, 45, or 46 just by looking at their covers.
So googling trying to find that panel from one of those comics brought me to a tangent on the Nexus of All Realities (instead of probabilities) and how in Marvel it can be a place or a person depending on which universe it is. In 616, it's Wanda; she's a Nexus of All Realities. Had to rewind back to the commercial and, sure enough, the commercial says Nexus "... anchors you to your reality, or the reality of your choice... " implying that there are multiple realities. And if she's the Nexus, this will naturally play into the new Doctor Strange flick.