1. Chapter 217(DBZ 23) P 7.6
Doesn't Piccolo in the 6th panel state something about Nappa's strength?.
2. Chapter 218(DBZ 24) P 14.3
And I'm pretty sure 3rd panel Piccolo says something like "incredible" or something in the context of Nappa surviving Tenshinhan's Kikoho.
3. And this one as well:
Chapter 219(DBZ 25) P 1.2
Second panel Piccolo, I'm sure says something about Nappa being invincible/unbeatable or something.
4. Chapter 219(DBZ 25) P3.3-3.5
And on this page Piccolo states that they are stronger, than Raditz and that they don't stand a chance.
5. Chapter 219(DBZ 25) P5.2
I'm sure something's stated about Nappa being unbeatable, while flying.
6. Chapter 220(DBZ 26) P2
And here the only way of winning is to grab his tail and if Gohan doesn't follow the plan then they are all doomed.
Also this:
Chapter: 320 (DBZ 126), P4.5
Freeza: “Son Goku had done well…With Freeza as his opponent, he was completely winning the fight through overwhelming strength…But the cornered Freeza wiped Planet Namek itself out…”
Kaio is the one who said that, not Freeza





