Unlike Vermont, which is an open primary, Massachusetts is only a semi-open primary. What this means is that registered Democrats cannot take a Republican primary ballot. However, if you are “unenrolled”, you may choose either a Rep or Dem ballot. This should blunt Nikki’s chances there. I think VT is the only possible state Nikki can win and even that window is starting to close.
Maine has the same system as Mass.
So now North Carolina has been called for Trump. Nikki is having a bad evening!