I'm fairly certain that nappa is lighter than verona.
Verona is slightly lighter than pebbled (that's what Colette told me and I think it's true based on my verona bag and my understanding of pebbled), but nappa is much lighter than pebbled. Nappa is only a hair heavier than the most lightweight leathers (merinos and athene/tuscania). Nappa is super light and verona is almost as substantial as pebbled, which starts to be on the heavier side for some with sensitivity to weight in their bags.
Of course the style of the bag makes a big difference in the weight of the bag. As I just found out from a handle change making my selene midi much heavier. And my athene Arianna is not a light bag(just smack average, when I weighed all my bags on my kitchen scale), for example, because of the giant thick rolled handles, even though the leather is super light.
Just wanted to pop in with that so no one gets the impression that verona is lighter than nappa. Definitely not.