I'm a doctor from the UK (where I pay tax) on an H1B Visa. I work in NYC and have a single taxed income in the US from the hospital. what's my status re US Tax return?

General overview https://www.irs.gov/pub/irs-pdf/p519.pdf  (US Tax Guide for Aliens)

First review this and determine your US tax status (resident or non-resident). You can be considered a US resident even if you don't have a green card if you meet the complicated substantial presence test described in this link:

https://www.irs.gov/individuals/international-taxpayers/determining-alien-tax-status

if you are considered a non-resident alien review this:

https://www.irs.gov/individuals/international-taxpayers/taxation-of-nonresident-aliens

TT does not do support non-resident returns, but has a partner who does. See

https://ttlc.intuit.com/community/forms/help/does-turbotax-handle-form-1040nr-for-nonresident-aliens/00/26295

If you are considered a resident then you can use TT. 

The biggest difference is that US residents pay tax on their worldwide income (but with a credit for foreign tax and a lot of tax treaty provisions to prevent double taxation, see e.g. https://www.irs.gov/businesses/international-businesses/united-kingdom-uk-tax-treaty-documents ).  Non-residents only pay US tax on their income earned in the US.