I think there are two issues here.
1) Unless you have a special arrangement you need a visa to work in the US anyway, details can be got from the US embassy web site- you may well have all the info and I'm not trying to teach you to such eggs! it may be subject to a letter of employment.
2) Most US operators want a US license because of the plane registrations, its quite easy to get the conversion from the ICAO commercial, just one exam for the IR, and one for the commercial, followed by a flight test and oral exam. Minimum training requirements prior to test apply- see web site
www.faa.co.uk
I think you also need the FAA license before you can be type rated
The pay can be piss poor for FOs even at corporate level.
Good Luck