According to Vermont Instructions for Form IN-111:
If you are a Resident, Nonresident, or Part-Year resident, you must file a Vermont income tax return if you are required to file a federal tax return, AND:
You earned or received Vermont income over $100, OR
You earned or received Vermont gross income of more than $1,000 as a nonresident.
Can I file a different filing status on my return than the one I used on my federal return?
Vermont requires that you use the same filing status that you used on your federal return. An exception to this rule applies if you are in a civil union or if you are a married couple residing in Vermont and your spouse is a nonresident of the state with no Vermont income. In this case, you may file separate Vermont returns.