Since your NRA spouse has no income, it may well be to your advantage to file a joint return. That's because the Standard Deduction if you file as MFS is $12,950; if you file MFJ it's $25,900. (The disadvantage of a joint return is that it subjects the NRA spouse's income to U.S. taxation. Since your spouse has no income, this is not an issue in your case.)
You can prepare an MFJ return in TurboTax, you just can't e-file it. You have to print and mail it, along with all the supporting documents required to obtain an ITIN for your spouse.
https://www.irs.gov/instructions/iw7
TurboTax has a help article on this topic:
How should I file my taxes if my spouse is a nonresident alien? (intuit.com)
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
