Why not try it the other way around.
Make a nailboard drawing then add a new sheet and copy over the views of your existing drawing.
When done, save over the existing drawing (after closing the original).
---edit---
Actually, i just tried... i could just copy over a sheet with a nailboard view without issue...
Maybe what you're missing is that you need to click back to the "model" section in the browser when it's displaying "cable&harness" so you can access the sheets again...?
---another edit---
The copied sheet does seem to lose that "cable&harness" environment after copying... so there is some loss in functionality.
@johnsonshiue, This might be interesting for you to look at.
Some screenshots:
original sheet with nailboard placed has "cable&harness"

But when copied over to a new sheet, this disappears:

My method of copying:
On drawing with nailboard, go to "model" and select the sheet with the nailboard.
Use CTRL-C to copy the sheet.
Go to new drawing and select filename in top of browser to add copied sheet by using CTRL-V.
(done in IV2018.3.2)
Niels van der Veer
Inventor professional user & 3DS Max enthusiast
Vault professional user/manager
The Netherlands