I am a J-1 visa holder therefore a nonresident alien. Can I use TurboTax to file my income tax return? Also, although I am married, my status is considered as single again since I am on a J-1 visa. Should I file as single?

As TurboTax does not support Form 1040NR, you cannot file with TurboTax.  Instead, you are advised to visit our partner, Sprintax who offers filing solution to our TurboTax customers.  See Visit the TurboTax/Sprintax site.

As a J-1 visa holder, you are considered as "exempt" meaning not counting days for two years starting from the date of your first arrival in the United States.  After the two years period, you will start counting days by using the Substantial Presence Test  to see if you qualify to be treated as a US resident for tax purposes.

For examples, see :https://www.irs.gov/individuals/international-taxpayers/alien-residency-examples

For nonresident, you can claim single as your filing status ONLY IF you meet the requirements:

See https://www.irs.gov/pub/irs-pdf/i1040nr.pdf under Filing Status / Married persons who live apart

If you qualify, you can file Single on your Form 1040-NR.