Goku vs Nappa (read the OP)

[Hector]

Goku: As he was right after the beam struggle with Vegeta.

Nappa: With the power he showed when he was knocked around during the greatest part of his fight with Goku (regardless of whether you believe it was his full power).

 

[Zippy]

Goku could hardly move "right after" the struggle

 

[SSJ2]

Goku loses. Kaio said it was doubtful that Goku could beat Base Vegeta after the beam struggle without using the Genki Dama. Kaio even went as far as to say Goku had no strength left. It looked like it was taking everything Goku just to activate Kaioken for evasion. He'd be luck to have a small advantage over Nappa in that condition, but it wouldn't be enough to bring him down.