If you and your wife are both considered nonresident aliens for 2018, you may not file a married filing jointly tax return. You instead need to file a nonresident tax return as married filing separately.
TurboTax does not support nonresident returns.
However we have a partnership with Sprintax offering a
nonresident tax filing solution to our TurboTax customers.
Visit
the TurboTax/Sprintax site for more info or to get started.