It is very difficult if not impossible to get a federal conviction expunged. If you read this article you will see that even in cases where the judge throws the charges out for lack of evidence, or the jury acquits someone of all charges, the federal courts will not expunge the record. In your case the conviction stands, making it that much harder. A lot of Nursing Boards bar licensing anyone previously convicted of a felony. You might want to get a second opinion from a federal lawyer in your jurisdiction, but I thought I should deliver the bad news first.
Here is that article:
Short of a pardon, you cannot get this expunged.
However, your concern is to be a nurse. Check the requirements for licensing for Nurses. The felony may not prevent you from becoming a nurse. Its not good but if it doesn't prohibit you from licensure perhaps if you explain the situation, how long ago, etc., the board will approve you. I don't know Nurse Licensure Requirements in Texas. Check here: Texas Administrative Code, Title 22, Part II, Chapter 217, Rule 217.4. This statute deals with nursing licensure requirements.
My understanding is the Boards review each application on a case-by-case basis.
If Texas is too strict, you might consider looking the requirement of other states. I know several attorneys who could not become licensed in Texas so went to another state to practice that had more lenient rules and easier bars.
There's nothing you can do at this point. A federal conviction is subject to collateral attack if constitutionally infirm for one year from the date the conviction became final. See 28 USC 2244 & 2255 re the AEDPA limitations period and the statute concerning a motion for a new trial or to vacate the conviction. Sometimes portions of the record can be sealed, but even there the order is supposed have a expiration date. In reality, sealed motions are for hiding informants. There is nothing to do. I wish I could give you better news.
This depends on what the exact sentence was. If you were placed deferred ajudication you may qualify for a non-disclosure. If you your case was dismissed you may qualify for an expunction. However, if you served jail time as a sentence on this case you may not be able to seal the record.