Normani sounds fine and she admitted (during her genius clip) that it's far from the most vocally challenging song, but, she wanted people to be able to sing along and the playful background vocals, pre hook and chorus are perfect for that.
My issue with her is her confidence. I just watched the rest of her genius interview and singing, and she couldn't even get through some of the raunchy parts without laughing and didn't fully commit. And when she did the outro written and recorded by Starra - the songwriter of wild side - she kept saying how shitty her take was in comparison and why she left Starra's vocals on it.
I don't like that. I get not being fully comfortable with the sexual stuff but she needs to at least believe in herself vocally and the songs she records and plans to push.