I think that she just looks a lot larger because Nakita is such a small cat. I know that when Pearl and Starr were kittens, Pearl was much beefier looking but Starr was longer and thinner even though they're only 2 months apart. Now Starr has gotten beefier and Pearl has gotten longer and thinner. Some cats will just be larger than others.

Right now my Ziggy still looks so tiny compared to all of my other cats but she's also been growing longer and gaining weight since I've had her. She may surprise me and become a large cat too.