So you could have two hackers who each tip each other off to companies that they have independently hacked. They can just claim each other's rewards since they had nothing to do with the actual attack?

It depends.

If there is any evidence that the hackers colluded with the tipper so they could both share in the reward (i.e. if the hackers get any % of what the tipper gets), then the tip would be treated as part of the hack and the tipper would not be eligible for the reward.

It's called an inchoate crime: conspiracy.