Plantinga argues: "the probability that our minds are reliable under a conjunction of naturalism and evolution is low or inscrutable. Therefore, to assert that naturalistic evolution is true also asserts that one has a low or unknown probability of being right."
So, if naturalistic evolution is true, then Plantinga's mind is not reliable. He has a low probability of being right about anything.
Therefore, we should reject his argument, as it is most probably wrong.