AIUI, there is a law that authorizes (mandates?) that states pursue estate recovery for anyone that has received Medicaid services over age 55. Of course, this was meant to apply in the era when Medicaid had assets tests, and thus estate recovery typically entailed going after one's home, since that asset wouldn't count in terms of eligibility. Of course, the ACA Medicaid expansion dispenses with the asset test, but does this fact that there is no asset test thus render null this estate recovery liability?
The little research I've done seems to have material from scaremongering elder law firms but also a few news organizations that say that this is a real thing. Of course, until someone who has gotten Medicaid expansion, then passed on, and then had his estate confiscated, we won't know if this is a real thing.
I plan on asking my state's governor's office and legislatures for clarity via statutes on the books that state this; otherwise, how could I be sure that some future state government looking to squeeze out a few bucks won't decide to come after my estate.
I think my default position is to start getting regular ACA coverage with my stated income at the bare minimum income of 138% of poverty + $1, and pay the premiums, and then just get the refund when my actual income ends up being lower. Yes, you can state any expected income you wish - how in the world is someone supposed to have the responsibility of predicting the future? - and if given a premium tax credit, you can get it all the way down to 0% of poverty when you file your taxes (you just can't get it during the year).