Just to make distinctions. Flyingfer, is the expert, but in states like MI the law allow them to intercept your state income tax.
While some States do allow for State tax refunds to be offset for civil debt (MI is one of them), there are certain procedural safeguards in place. I will use Michigan's as an example because (a) it is typical and (b) it is the State that was mentioned.
First, I refer you to this web site: http://www.michigan.gov/taxes/0,1607,7-238-43513_44135-156357--,00.html#garnishment
It is the Michigan Department of Taxation and what they say is official.
First, they cannot take the refund without notifying you in advance. Michigan requires the State Tax Department to send you a "Request for Information Notice" and, more importantly, a form titled "Income Allocation For Non-Obligated Spouse (Form NOS-743)". This form is similar to IRS Form 8379 Injured Spouse Allocation. While they can take any refund attributed to the Obligated Spouse, they cannot take any refund attributed to the Non-Obligated Spouse. These forms allow you to recalculate your refund and attribute it to each spouse separately without you losing the benefits of filing Jointly.
Back to the OP's issue: Since your spouse has no income, none of the refund can be attributed to her. Therefore, even if they do file a lien against your State Tax Refund, they can't get any of it, since all payments of the tax were made by you. Fill out the form, send it in and thumb your nose at the creditor.