hmmmm. Haven’t heard of it being there too often but I usually see Nissan ones on the Right side of the Tranny.
You can make your own no problems and avoid having to purchase the Nissan Original.
When I changed my engine the tranny came with it. The tranny had a good switch, so I didn’t need to buy a new one. 5 Speed reverse light switch costs $35USD for my car. I’m sure it can be sourced somewhere else even cheaper.
I doubt a relay and switch would cost $25.00. You can piece everything together from Crappy Tire for ~$5.00.