Nicki and Katy

Neither, they both came out of it looking worse than before.

Nicki came out of it looking like a petulant child throwing her toys out of the pram, and Taylor came out of it in the only way she could given the cheap ploy Nicki used. Katy came out as the real winner, but Taylor will be the one getting that VMA I guess.

2 Taylor Swift - 1989
62 Taylor Swift - Red
N/A Nicki Minaj - The Pinkprint

Taylor

Queen Katy came out above both

MTV/VMAs, Bad Blood (as a song/video) all won.

Nicki and Taylor both lost
Katy's attempt to jump in was largely ignored and boring but I doubt she cares

MTV, Katy.

MTV won

Neither, both got bad publicity for this.