Moral naturalism is a kind of moral realism which views moral properties as natural properties, similar to those that are dealt with by the natural sciences, and that these moral properties can be reduced to non-moral features of the world. Is this view consistent with the Objectivist meta-ethical and ethical view?
The issue of morality centers around one question: what is good, i.e. what does value consist of?
According to Ayn Rand, the value of anything, be it an object, or an action, or even an attribute, is in how that thing relates to a standard of value. In other words, to be good is to be good for something.
According to Ayn Rand, nothing can be considered valuable outside the context of some ultimate value which serves as the standard for determining the value of everything else.
The phenomenon of life is what makes the concept of value possible (in a dead world, there is no being to whom anything can be of value), so life is the standard of value.
For man, man's life is the standard of value.
I think it is pretty safe to say that Ayn Rand's views are at odds with Moral Naturalism, which appears to be searching for "value" in each object, rather than in how each object relates to the standard of value.
It sounds like moral naturalists are trying to defend the truth of morality by claiming that morality is in things. I think this is a mistake. Morality is objective, but it is not in things. It is in how each thing relates to (i.e. how and if it serves) the standard.
My first reaction to a question such as this is: what is it, i.e., what does "moral naturalism" mean? I couldn't make much sense of it from the description in the question, so I checked Wikipedia and found an article titled, "Ethical naturalism." From that article, it does not appear that "moral naturalism" is a specific moral theory, but rather, a general "umbrella" topic or category for classifying ethical systems and studying them.
The Wikipedia article includes a list of eight different examples of ethical naturalism, of which Objectivism is #5. It does not appear from the Wikipedia article that the topic is intended to imply that naturalistic ethics has to be intrinsicist (or Aristotelian). Otherwise, the list of examples in the article would be considerably shorter (and probably would not even include Objectivism). It also appears that the meaning of "ethical naturalism" is broad enough to include Objectivism as a valid example. I find it hard to dispute that inclusion, although there are certainly vast differences between Objectivism and other examples in the list.
I also don't think the umbrella topic is necessarily intended to shed much light on which ethical theory is "best" -- for whom and for what end. It's apparently just a springboard for academics to launch into myriad studies, discussions, debates, critiques, etc. -- which Objectivists may find intellectually "sharpening" and focusing when comparing and contrasting Objectivism with other philosophies and methodologies that may bear some superficial similarity to Objectivism. Academics even debate about the very definition of "ethical naturalism."
As a further check, I also tried looking up "moral naturalism" in The Harper Collins Dictionariy of Philosophy, 2nd. Edition, by Peter A. Angeles. I actually found two entries, which cross reference each other: "ethics, naturalistic," and "naturalism, ethical." The first entry lists three definitions of "ethics, naturalistic," basically reinforcing the essence of the Wikipedia article. The second entry (p. 201) describes "naturalism, ethical" as "the view that no sharp demarcation exists between facts about the world and judgments (evaluations) about the world and how humans ought to act in it. Moral judgments contain facts about natural phenomena. Examples...." Viewed as a broad "umbrella" category for the study of related instances, that seems very reasonable and uncontroversial from an Objectivist perspective, as I understand it, and Objectivism would certainly qualify as an instance, as long as "no sharp demarcation" isn't taken to mean intrinsic.
For those who may want to learn more about how Objectivism derives values from facts of reality, there is an excellent collection of excerpts in The Ayn Rand Lexicon under the topic of "Values."