I believe this impression is created by surveying the more "popular" part of the literature. Leiter in Nietzsche’s Theory of the Will describes the general approach as routine:
"I am concerned with the notion of “will” familiar from general philosophy of action, both contemporary and historical, namely, the idea of a human faculty, whatever its precise character, that stands in some kind of necessary relationship with action. Such a faculty may itself be causally determined, or it may be autonomous of the antecedent causal order; its status may implicate questions of moral responsibility; and such a faculty may not exist at all. A theory of the will is one that sheds some light on these issues."
"Free will" is often used as an idiomatic label, which indicates selecting a particular aspect of the human action, namely self-determination and its relation to causal physical laws, often accompanied by implications for moral responsibility. This label, sometimes contracted to "freewill", is unsplittable and can be used even by those who believe that there is no will, free or otherwise. Philosophers (and psychologists and neuroscientists) who wish to focus on other aspects may use different terms, like "volition" (Roskies, How Does Neuroscience Affect Our Conception of Volition?) or "antecedents to voluntary action" (Nachev and Hacker), etc.
A recent trend in the philosophical literature, stimulated by experiments in neuroscience starting with Libet's, is to focus on another aspect: whether or not voluntary action is initiated consciously or unconsciously, regardless of whether it is "free". Correspondingly, the label is changed to "conscious will". But this still does not imply any "will" faculty, conscious or unconscious. Wegner's Illusion of Conscious Will is the book that launched what is now called "willusionism" into broad public consciousness. A systematic rebuttal of Wegner, Mele's Effective Intentions: The Power of Conscious Will, uses the same label. Some arguments for unconscious will are discussed under What counters are there to Spinoza's argument that acts of free will create infinite regress?
It may surprise some people, but Nietzsche was a forerunner of willusionism, and developed a powerful phenomenology undermining the folk notions about conscious "willing". All that without the measuring sophistication of Libet-type experiments. We do not experience our thoughts as "willed", argued Nietzsche, so if "willing" is causing, and our actions are caused by our thoughts, then they are not caused by "us" at all. In Twilight of the Idols he writes:
"The “inner world” is full of phantoms and will-o'-the-wisps: the will is one of them. The will no longer moves anything, hence does not explain anything either — it merely accompanies events; it can also be absent. The so-called motive: another error. Merely a surface phenomenon of consciousness — something alongside the deed that is more likely to cover up the antecedents of the deeds than to represent them. …What follows from this? There are no mental causes at all."
Compare this to Wegner's:
"The initiation of the voluntary act appears to be an unconscious cerebral process. Clearly, free will or free choice of whether to act now could not be the initiating agent, contrary to one widely held view. This is of course also contrary to each individual’s own introspective feeling that he/she consciously initiates such voluntary acts".
Of course, Nietzsche and Wegner have quite different motivations for their views, the latter cites causal physics and Libet experiments, the former, while also being unduly impressed by deterministic physicalism of his time, has a deeper motive. No will - no moral responsibility:"the whole realm of morality and religion belongs under this concept of imaginary causes". One can find this aspect more recently developed by Strawson in Impossibility of Moral Responsibility among other places. But there is one big difference between Nietzsche and determinists, like Wegner and Strawson, the Leiter points out:
"it is precisely because Nietzsche is a radical empiricist skeptic about laws that he eschews the language of classical determinism. Nietzsche’s “official” view (strange as it may seem) is that ours is a world of token necessities, not lawful necessities..."