The sort of #Mithridatism that is in the 3rd #Riddick movie is theoretically possible, as it can be done with snake venom. But it does rather hinge on how well the biochemistry of the alien world matches Riddick's Furyan #biochemistry.
Of course, it's a bit of a suspension of disbelief point in the Riddick universe that all planets seem to be capable of supporting Terran life; even Crematoria which has (per the effects department) a continuous semi-circle of combustion circling the planet once per day eating up the oxygen in the atmosphere. (And, magically, no convection currents causing a permanent windstorm.)
Riddick certainly seems to be able to survive on the alien organisms as food.
Consistent planetology and ecology is not this franchise's strong suit. Vide the organisms in #PitchBlack destroying their own food source entirely, yet being able to survive in large numbers for decades. In the real world, overpredation causes population collapse.