You don’t need the Nvidia app to avoid CTD if you want to play with DX11- for example, MSFS runs better with DX11 than DX12. I’ve posted many times on the forum about how to fix CTDs during MSFS 2020 loading, so I’ll write it again here 
We already have a forum topic about this bug - CTD during MSFS 2020 loading. Here’s the link to the thread:
There’s currently a workaround available and even several of them.
Before trying any workaround, please make sure to participate in the linked thread to confirm you’re also affected by this bug.
Here come the workarounds (click to expand)
Until Nvidia fixes the application and Asobo MSFS 2020 please check what happens if you select DX12 instead of DX11 by manually editing cfg file.
To do this, you need to edit usercfg.opt file and modify the line
PreferD3D12 0
Change the number 0 to 1
and save the changes.
OR
If you need Nvidia app also select DX12
OR
If you need NVIDIA app and want to play with DX11, delete NGX folder - you’ll find it in C:\ProgramData\NVIDIA.
OR
If you don’t need NVIDIA app and want to play with DX11, uninstall NVIDIA app and then restart PC.
FYI, If you want to use the latest Nvidia drivers starting from version 580.88, DX12 must be selected in MSFS 2020 settings. With drivers newer than 577.00, there will be CTDs if MSFS is running in DX11 - even without the Nvidia app. If you use driver version 577.00 or older and want to play DX11 in MSFS 2020, the Nvidia app should not be installed.