にほかならない: identifying exactly what something is
Strongly identify a result's cause or something's true nature. Distinguish this from suggesting a possibility, and check why a forceful assertion does not replace evidence.
This and nothing else
この成果は、全員の努力の結果にほかなりません。 means that this achievement is precisely the result of everyone's effort. Following the noun 結果, the expression strongly identifies the achievement's nature rather than suggesting one possibility.
私が求めているのは、正確な情報にほかなりません。 means that what the speaker wants is nothing other than accurate information. Connect the subject before は with the noun before にほかならない to identify what is being asserted.
Emphasizing a cause
成功したのは、皆が協力してくれたからにほかなりません。 explains that success came precisely because everyone cooperated. The reason clause is joined with から before にほかならない emphasizes it as the essential reason.
Despite the ending ない, neither the cooperation nor the success is denied. The whole expression strongly affirms the preceding content by excluding other explanations, so do not reverse the meaning based on the negative ending alone.
Direction and force of the evaluation
これは一つの例にすぎません。 lowers the scope or significance by calling something just one example. これは一つの例にほかなりません。 identifies it as precisely an example. Both involve limitation, but the emphasis differs.
This firm assertion suits formal explanations or arguments. It says that the speaker strongly identifies a nature or cause, not that the claim has been independently proved true.
Quick check: Does これは努力の結果にほかならない。 deny that this is the result of effort?
Show the answer and why
No. It strongly affirms that this is precisely the result of effort. Read にほかならない as a whole unit.