You would be best looking for a programmable pointer of some sort.
When I have to give public presentations, I use a Pageflip Dragonfly quad pedal. This is a bluetooth device that sits on the floor, and is controlled with your foot. Mainly intended for musicians with digital music displays (such as Onsong on an iPad), but can be used with anything that accepts a bluetooth keyboard.
The Windows based programming interface was not very accessible, but with object nav I was able to get one of its profiles set to send the correct arrow keys for previous and next navigation with two of its pedals, and its two other pedals set to volume up and down.
I don't know if looking for a pointer that can send the right keys out of the box will work for you, but looking for one that can send whatever you set it too, might be a solution.
Also, you might look into remapping some of NVDA's keys to have the effect you want, through the emulated system keyboard keys section of input gestures.