1. The uniform doesn’t match up with the Nijigasaki one. Take a look at the ribbon, maybe the skirt color, among other things.
2. The gym uniform isn’t really a Setsuna thing. (Also, none of Setsuna’s idol outfits are here.)
3. I went to this cosplayer’s Booth page and saw she typically lists which series a given cosplay’s from. For this set, it’s missing. (The title itself doesn’t suggest Love Live either.)
Seems like it’s just a generic, quite nicely done schoolgirl cosplay. The Setsuna (Nana) glasses and braids are more just a coincidence.
That said, I would LOVE to see her try a Setsuna cosplay. She could really pull it off.