You can use USB-8452's onboard pull-up resistors to operate USB-8452 at a pull-up voltage of 1.8V.
You can see this information in NI-845x Hardware and Software Manual
as shown below.
Since an external pull-up to 1.8V is outside of USB-8452's specifications, NI can not guarantee it working properly at an external pull-up voltage of 1.8V. NI suggests to use internal pull-up resistors for 1.8V.