I'm guessing there's no strain on Nappa's body in this fight, otherwise it wouldn't be one.
Nappa might be able to win this, due to being much smaller and more agile than an Oozaru Vegeta, but Nappa's not the genius fighter that Goku is, and in his situation (although a lot stronger) I'm not sure if Nappa would be able to use Vegeta's size to his advantage like Goku did.
Nonetheless, I'm gunna have to give this to Nappa, seeing how Goku fared against Oozaru Vegeta, despite the huge power difference.