Nephi is referencing the secret combinations here, and emphasizing that they are not of God - regardless of how they might be presented. By their very nature, secret combinations are in “darkness” or secrecy. Nephi states that God does not work in secret.
Narrative: Verses 23-33 form an interesting set of verses. Verse 23 begins with a very direct address to an audience “behold, my beloved brethren.” The text that follows is internally consistent in discussing the way the Lord works (contrasted with specific ways he does not work). Nephi uses the phrase “I say” five times between verses 23 and 28, almost once per verse. Each of the verses reads more as preaching as prophecy. Where the rest of the chapter has been discussing a prophetic vision, the language of these verses are a polemic against some very particular situations.
Of course the situations come explicitly in the context of the gentiles’ “envyings, and strifes and malice” (verse 21), but the specifics of the texts read more as an aside than the types of descriptions that Nephi has given in other descriptions of the “future history.” All of the other examples have been quite to the point, a description of events. These verses pause in the description for a very specific polemic.
While of course it is speculative, I suggest that these verses are an aside triggered by a confluence of similarities between the future gentiles and experiences that are very close to Nephi’s experience. When Nephi expands into particular denouncements of certain actions of the future gentiles, I suggest that he brings to those future events the past frustrations of his attempt to be political and spiritual leader of his own people. To support this hypothesis, the verses need to be seen both in the context of an aside, and specifically in reference to Pauline vocabulary and themes that enter into the text.