Übersetzung - Spanisch-Englisch - El valor crea vencedores; la unión crea...

judging on the context, 'el valor' is better translated as 'courage'

Yes, I agree with you: "Courage makes winners and unity makes invincible/undefeatable people."

Nego and Freya :

I believe "el valor" (of a person) is the combination of merits, correct behavior and noble feelings a person keeps during life.

"valentia" means courage.

It's quite different "uma pessoa valente (courageous)" and "uma pessoa de valor (with merits)"

What do you think?

Maybe bravery ? Anyway, I think it has meaning either way.

Courage is the best option. The cite is from Casimir Delavigne's Messéniennes:

Le courage fait des vainqueurs;
La concorde, des invincibles.

Cf. Troisième Messénienne, Du besoin de s’unir après le départ des étrangers.