I'm not a nurse, so I'm not familiar with nursing employment policies regarding positive TB tests. I do know that positive tb tests from immigrants to the U.S. is very very common. If you have a negative chest x-ray, then you're just fine. I would think that would suffice for any type of employment. I used to work with a number of immigrants from South America, many of which tested positive for tb. They also had negative x-rays and were allowed to keep their present jobs.
I also think, in your case, that prophylactic tx may do more harm than good. For what it's worth, I agree with the doctor you saw in Texas--you do not need tb tx.
I'm sure others who are more knowedgeable will be along soon.
Current dx: Rheumatoid Arthritis
Suspected dx: UCTD/Early Lupus
Current Meds: Enbrel, Plaquenil, Aciphex, Ultracet, Zyrtec, Allavert-D, Zantac, Tylenol PM
Past Meds: Relafen, Vioxx, Mobic, Voltaren, Sulfasalazine, Entocort, Prednisone, Humira, Reglan