I lived in two states in 2020. What if the total in boxes 16 for both states, exceeds what is in box 1?

What are the two states?   It is possible for State wages (even in a single state) to be higher than Federal wages because of the difference in how some employee benefit plans are treated.

It may also only mean that there was double  withholding on the overlapping amount.  That is, you employer withheld state tax, for both states, on a portion of the box 1 amount.   This may require a workaround in TurboTax.

Sometimes you have to ask your employer what it means.