Parvati was playing the game plain and simple. She had no feelings for Nathan. SHe just flirted with him so she could get closer to him and JP who she thought was going to run the game. But once she relized that Jenny, Cristina, Stephannie, and Rebecca had control she dropped Nathan and JP like a bad habit. I can almost guarentee that you will see a lot more flirting from Parvati towards Adam and Brad rather then Nathan now.