> Some consider those distinct as they state the UBI would not decrease with additional earned income.

They are the same; both have the effect that benefits are “drawn down” through marginal taxation of outside income, though Friedman’s specific NIT proposal had an exceptionally high (though still lower than the effective drawdown rates often faced by means-tested benefit recipients) marginal rate (50%) for the the below-break-even bracket (essentially, the bracket whose outside income was less than “Effective UBI”/(bottom tax rate)), which most UBI proponents would reject in favor of consistently progressive rates. But this isn’t an inherent feature of generalized negative income tax.

UBI may not decrease, but progressive taxation on income, coupled with adjusting rates (to pay for the substantial increase in federal expenditures) will have the exact same mathematical effect.