The filing status of an individual is based on their marital status as of the end of the tax year they are filing for. A nonresident alien generally cannot file as Married Filing Jointly.
The Married Filing Jointly status is available only to resident individuals who are married as of the end of the tax year.
There is one exception. If you are married to a US citizen or US resident for tax purposes, you might be able to file jointly. This cannot happen through Sprintax as you would have to use a resident tax preparation platform such as Turbotax.