How do you erase the nand flash on this router?

Do you want to erase the whole flash? You need to do in uboot.

And then what would I do

you need to tell the purpose so that I can answer.

Use a UART adapter and connect to the router, then stop in uboot, then use nand erase all

Oh alright I don’t have a uart adapter so sounds like it’s not possible for now. Thank you