@Jimx7 - Welcome to SNB. If at all possible, you really want to hard-wire the NVR for max reliability. If you can't do ethernet (perhaps inside some
surface raceway?), then how about
MoCa over TV coax? Also, avoid powerline adapters; operational certainty is too low due to electrical circuitry being a poor network medium (they may work, they may not, they may start out working, then degrade at random, or all at once, or only when you run the dishwasher, etc.) -- just not a good long term solution.
If you absolutely cannot hard-wire, then you'll want a
wireless client bridge, which acts as a wireless client radio for whatever you wire to it. As
@OzarkEdge noted, a client bridge is
not an access point, nor is it a repeater, nor would I use either for this purpose; ideally, you want the NVR to have an exclusive uplink.
For a hardware choice, for simple/cheap, you could use an omni-directional, multi-purpose product, like this $55
Asus RP-AC55 running in Media Bridge mode, connected to your router's wifi. Alternatively, if you have enough free 5Ghz airspace, you might also consider a directional, point-to-point product, but it's unlikely you'll need that much dedicated bandwidth for just two cameras, so something like that Asus ought to suffice.