my great granddaughter is in the NICU. Is there it true I can't visit unless the parents are there. I drive almost 450 miles to see the baby

Speak to the parents. The baby's health privacy is governed by them. If the hospital allows NICU visits and parents OK with your visitatation go see your great grand

Call the hospital. And ask them.

I don't know that answer but you can look up the policy on the hospitals website