New Hampshire has a relatively small, highly engaged and educated (and with a very inflated view of self-importace) group of voters to make such an outcome entirely possible.
The bigger challenge is whether Bernie Sanders can continue to put up enough of a fight to keep Democrats from voting in the Republican primary in sufficient numbers.
Democrats can't vote in the Republican primary, but undeclared liberals can. Hopefully they will head for the Democratic ballots, but more likely they will head for the Republican ballots. Allowing undeclared voters to participate in primaries is a bad idea.