The personification of "Nature," typically as a feminine force or being, is a common literary trope seen throughout 18th century literature. Common Sense is no exception: in the text, Paine appeals to "Nature" as an authority figure, beginning as early as the introduction:
The laying a Country desolate with Fire and Sword, declaring War against the natural rights of all Mankind, and extirpating the Defenders thereof from the Face of the Earth, is the Concern of every Man to whom Nature hath given the Power of feeling[.]
Both God and "Nature" thus become, in Paine's rhetoric, figures of power and authority that transcend the monarchy. God's power relative to the monarchy lies in the supremacy of his moral position: he determines the moral code by which human beings should live—according to Judeo-Christian values. Kings and magistrates do not have that power.
Similarly, Paine personifies "Nature"—or the natural order of things as he sees it—according it power over mankind that transcends the abilities and agendas of the monarchy. "Nature," personified, is an extension of the voice of God, presiding over biology and natural phenomena instead of morality. By giving Nature this agency and supremacy through personification, Paine provides himself with another authoritative voice through which to speak and condemn the monarchy.