anyone know if we can change the default Received Not Invoiced account in Netsuite? Ours is all messed up and we are thinking of just starting clean with a new one, but I can seem to find a way to change that account for Receipts and bills

I don't think you can. There are a variety of processes/flows in NS where it's tied to a specific system account where it's not changeable.

Yeah, can't be changed - but you can probably wipe it out effectively by doing the whole vendor bill variance process.