First if you disable your AMD IGPU then it would also disable your AMD Driver since you have no AMD GPU installed except your Nvidia GPU card.
No need to disable your IGPU in BIOS because BIOS will automatically switch from IGPU to your GPU card when you install it as the Main Display Adapter unless you have the IGPU set in BIOS specifically as your Main Display Adapter. In that case I would put it in "AUTO" .
If you do or do not have a GPU card installed then I would still enable the IGPU again in BIOS.
If you look in Device Manager you should see both your AMD IGPU and Nvidia GPU Card without errors.
Another good reason not to disable your IGPU in BIOS is in case your GPU card goes bad or you need extra Video outputs you can use your Motherboard's Video Outputs if needed.
There might be some conflict between your AMD VGA and Nvidia VGA drivers. So to avoid this I would just install the minimum AMD Driver Package or just have Device Manager install the AMD VGA Driver and it associated programs needed to run the AMD VGA driver.
