You should put it directly on your legit account. Don't ever, ever, ever associate the accounts in any way. Even gifting between them looks suspicious. If you put the NX on a hack account just to gift your legit account when your hack account gets banned there's always that slight chance the legit account will go with it.
It really depends on the hacks u use, if u use noticible hacks like ******'s(not gonna uncensor name because u all know what it is) ghosting. Then put it on the legit acc. If u just cham or something then go ahead put it on ur hacking acc.