In the revamped version of the nexus mind Cayde-6 says that the vex upgraded it with tech from the Vault Of Glass...but that's not possible because the vault is another plain of reality created by the vex and they also can't manifest the power that they have in the vault outside of it. Otherwise we would be seeing gorgons all over patrol. But it is entirely possible they built the new nexus inside the vault, but did not give it world altering abilities. Just a thought