You may be misunderstanding the meaning of "nonrefundable." If a credit is nonrefundable, it means that it cannot reduce your tax to less than zero. In other words, it cannot make you get a refund of more than the tax you paid during the year through withholding and estimated tax payments. But if your total tax is more than zero before the credit is applied, the credit can reduce your tax. If your tax is lower, your refund increases.
