I immediately thought she could be friends with Chihara because they are so different. They won't compete, and Chinatsu knows it. Chihara also will keep listening to her, I reckon, no matter how empty of real content her talks might be. Considering how awkward Chihara is, Chinatsu can keep teaching her stuff, like makeup/trendy clothes, feeling good about it. Maybe it's not a fully equal relationship, but it's a functional one. It's also better than one between a boss and goons. Of course this could be toxic as well, but it didn't seem like, since Chinatsu didn't create purposefully stupid nail art for Chihara or show other signs she would only be with Chihara to make fun of her.