Okay - my guess this week: Natalia Azoqa. It only works if Natalie and her end up on the same tribe after the swap. Since she was so adamant on this week's episode about getting Natalie out, I think she'll try again. If she does, I predict it will backfire as the new tribe realizes she's more of a threat than Natalie.
In Natalia vs. Natalie, I think Natalia Azoqa loses!