Installing 3/4" solid wood hardwood flooring over 1/8" DreamHome insulayment onto 23/32nd OSB subfloor

My guy at the flooring company tells me for solid wood to use nails, he wasnt sure what size though

Reading online other people say staples have a stronger hold

If I nail it, I've gotta choose between 1.5" or 2" nails, from reading I understand that I dont want the nail to penetrate all the way through the subfloor, so I'm thinking a 1.5" nail would be best, but then lumber liquidators (where I bought the underlayment) is telling me to use a 2" nail

Does it even matter? Seems everyone has their own opinion on nailing vs stapling, but if I do go nails, 1.5" or 2" which will be better?