Personally, i'd trace the cluster back to the loom and find out if the other taillight has the loom already run to it. Unless Nissan went to the hassle of not standardising this for LHD and RHD models. (I know my Mazda 6 have identical looms at each cluster and only one reversing light/fog)
If not - I'd cut that wire and run a parallel link wire over to the cluster to feed it. THEN when you switch on the reverse lights, have a mate hold the loom. If you smell smoke/it goes on fire then tell him to stop, drop and roll.
Actually on second thoughts, don't do that - you might be better to swap to low draw LED bulbs and save the hassle.
No expert though, but trial and error always works for me.
Will that effect fogs or anything?