It's down to Trump v. Nikki

Nikki pros: Domestically, she's a fiscal conservative, while Trump is a left of center economic populist/protectionist. She only lies as much as an average politician, maybe even a little less. She seems relatively intelligent, and principled enough to occasionally push back against her own base. For Republicans who want to beat Biden, she's more likely to.

Trump pros: He's not a neocon, even if he's not a realist or antiwar exactly. He's funny.