Whoa guys, a little hostile today, are we? Just because you hate LG's interface, doesn't mean everyone does or even should. I, myself, don't like it either but OP came here asking an honest question about modifying his Nexus 5. We could at least have the decency to tell him what we know, or not respond at all.
Anyway, OP. I personally do not know of any way to flash the G2's ROM to the Nexus 5, or any custom ROMs that were inspired by the G2. Your best bet is to try to download something from the Play Store that mimics what you like on the G2. Just doing a quick search, I found this app
. I haven't tested it or anything so I'm not sure how well it works, it's just one of results that came up from searching the Play Store. Seems legit, but like I said, I can't vouch for it.