If an infant Predator, say 3 or four days old was the same size as a chest burster, could it REALLY break through a human's chest?
The answer is no, Predator's are built like humans, they don't have the right mechanical build or strength per size weight ratio to do what a chest burster can, much less a full grown Alien...
The Alien could burst out of the chest because it could snap like a whip (it was built like a snake) and it's head was durable enough to withstand all of the pressure of snapping ribs, which by the way are not pleasant.
Now if the Predator wasn't armed with anything, it couldn't match that kind of durability, unlike in AVP, the Alien would be snapping it's arms around with great force, enough to snap ribs and skulls, and the Predator wouldn't be able to even get a blow on it.
Now Predators are extremely strong, they probably are on some kind of advanced steroid, stimulating their muscles to peak perfection, but not even the world's greatest athelete can compete with a gorilla in a brawl, it's just the way their built.
Now in a fight, the Predator wouldn't brawl with an Alien, he would probably set up a trap or two, and trap it, and kill it with what ever it pleases. A Predator would kill an Alien 10/10, but not in a straight up brawl like in AVP.
BTW, a Predator could lift a lot more than an Alien could, like if there were a 1,000 pound bar bell than the Predator could lift it and the Alien couldn't.
But that doesn't do the Predator much good in a fight.