If you have made alot it might be worth moving to a country without capital tax for a few years
Sadly in the US unless you renounce your citizenship (and to do that requires you gain citizenship in another country first) and pay an "exit tax" simply moving to another country doesn't erase any tax liability.
Still people shouldn't get tax advice from the internet.
If it is a small sum honestly the IRS has bigger fish to fry. The IRS audits less than 0.5% of tax returns for people making less than $250,000 per year. They aren't going to spend the manpower to track down some guy who had a $300 capital gain on some Bitcoins a couple years ago.
If you have a significant amount of wealth you are already use to dealing with the IRS (they concentrate on the "top") and likely already have professional tax support. If you suddenly find yourself in this latter category and don't have professional support ... get it.