I'm not from Netherlands, but from a different European country. I don't have first hand experience with this.
However, here is the read:
https://www.irs.gov/businesses/the-taxation-of-foreign-pension-and-annuity-distributions
The interesting part is:
"If you are a U.S. citizen or resident, in addition to the requirements set forth in the relevant treaty article, you will also need to consider the so-called "saving clause" (typically found in Article 1). The saving clause preserves the right of the United States to tax its citizens and residents (subject to certain exceptions) on their worldwide income, as provided under U.S. law, as if there were no treaty. If there is no exception to the saving clause for the relevant Pension/Annuity article and paragraph, then as a U.S. citizen or resident your distribution would be taxable in the United States."
Essentially, once you move to the US as LPR, you will lose your tax residency in Netherlands. If you're not a resident of Netherlands, my understanding is, you won't get taxed on your retirement there.
However, US will treat it as income and you'll have to pay taxes on it.
Others can correct me.