If Piccolo was forced to fight Broly before either Goku or Vegeta could arrive, do you think that he would've been able to hold his own against or maybe even kill Broly in his base form? Based on what I've seen, I believe that he could indeed fight against Broly, and if he was efficient enough against him and realized that Broly becomes more powerful and adept the more he fights, Piccolo would be able to eliminate him. He'd probably need to finish Broly off with a Special Beam Cannon, though, since just a regular energy attack, like what Super Saiyan God Vegeta used to try and kill Broly didn't work and allowed him to enter his Wrath State. The Special Beam Cannon would pierce through his body and deal fatal damage that Broly likely wouldn't be able to heal from.