That's an interesting interpretation of Nicole~ Certainly, you can make a solid argument for her being a subby girl deep down, one simply acting as a service top to win over her crush, heheh.
When writing Nicole, however, I envisioned her as the type of person who'll act shy, cutesy, and girlish to lower people's defenses and to endear herself to others; but when she smells an opening, she'll charge forward like a shark in a feeding frenzy, a domineering girl who'll take a mile when given an inch~
Nicole does hold genuine affection and attraction towards Ann, and wants to make Ann happy in her own twisted way—but in my vision of her, her possessive streak and her utter disregard for Ann's boundaries are far from being merely performative, heheheh~