If I understand your question correctly, you received a Commercial Pilot Certificate, Instrument Rating, and Multi-engine Land rating issued by the FAA under 14 CFR Part 61. You want to know if flight time you acquire in South America in an "N" numbered airplane (an aircraft of U.S. registry), after having received FAA issued certificate/ratings in the U.S., can be logged and counted as flight time in accordance with FAA regulations?
The regulation below (14 CFR 61.51 (j) (a)(1)) states that you can count and log that flight time, as long as the aircraft involved have either a standard or special airworthiness certificate . Applying for a job in the U.S., with respect to a company's flight time requirements (logged in accordance with 14 CFR 61.51), should not be an issue.
I don't know what you mean in the last part of your question - "If so what can those options be."
14 CFR 61.51(j):
(a) Aircraft requirements for logging flight time. For a person to log flight time, the time must be acquired in an aircraft that is identified as an aircraft under § 61.5(b), and is—
(1) An aircraft of U.S. registry with either a standard or special airworthiness certificate;
(link to 14 CFR 61.5(b) above is mine)