I don't think Millenials will necessarily swing to the right, but many will stay home because they won't be enthused about Hillary.
Where's your evidence for this assertion? Every poll I've seen has Hillary dominating among Millennials, both in the primary and the general election. For instance, the most recent CNN poll has her leading Romney 63-34 among 18-34 year olds, a bigger margin than Obama won them by in 2012. Seems like you're projecting based off your own personal bias here.
Wait till they find out how much a warmonger 3rd way corporatist she is.