Really, no need to. Go AMD when you want to upgrade anyways but don’t throw away a perfectly fine GPU. The difference between AMD and nVidia is that AMD works out of the box and for nvidia you would have to do one click or command to install the driver. That’s it.
Sure, if you dig deeper it is much more nuanced. But unless you have some unusual use case beyond gaming (which might actually compell you to go nvidia) just stick to what you have.
The funny thing is that it actually used to be the other way around when it was still ATI. The ATI drivers sucked ass so nvidia was almost mandatory if you wanted to run Linux.