Grading: (1) Its chain is "sahih" from the side of Zuhayr (Ibn Mu'awiyah al-Ju'fi), and from the side of Sharik bin Abdullah (al-Nakha'i) it has the potential to be graded "hasan".

Identification of narrators and research: Al-Nufayli is Abd bin Muhammad bin Ali bin Nufayl al-Harrani. Abu Ishaq is Amr bin Abdullah al-Sabi'i.
Technical note / Defect ('illah): His explicit statement here that he heard from Qutham bin al-Abbas comes through the narration of Sharik al-Nakha'i, and Qays bin al-Rabi' agreed with him on it (see: al-Husayn bin Ali al-Karabisi's book "al-Mudallisin", as cited by Mughlatay in "Ikmal Tahdhib al-Kamal" 10/208, and Ibn Abi Asim, "al-Ahad wa al-Mathani" 399).
Important point: Ibn Ma'in was asked (as Ibn Asakir 42/393 reported): Did Abu Ishaq al-Sabi'i meet Qutham? He said: "Yes, on the road to Khurasan." Therefore al-Karabisi's rejection of this report as false in "Kitab al-Mudallisin" - on the basis that inheritance means literally the inheritance of wealth, and that Qutham was martyred in the time of Umar or Uthman - is not correct. For the one whom Abu Ishaq al-Sabi'i met undoubtedly lived on until after the caliphate of Ali. Ghunjar, the author of "Tarikh Bukhara", dated his death to the year 57 AH, and this is what is correct about his death. Moreover, inheritance here means "knowledge", as Isma'il al-Qadi said (which will come with the author immediately after the report).

Technical note / Defect ('illah): The reason we are certain that Abu Ishaq's explicit statement of hearing from Qutham comes through Sharik and not through Zuhayr is that al-Hasan bin Ali bin Malik al-Ushnani narrated it, in Ibn Asakir (42/393), from al-Nufayli, from Zuhayr, from Abu Ishaq, with the words: "It was said to Qutham …" (i.e. using the passive form). Likewise Ahmad bin Abd al-Malik bin Waqid narrated it in Ibn Abi Shaybah (14/117), and al-Mu'afa bin Sulayman in al-Tabarani's "al-Kabir" (19/86), and from him Abu Nu'aym in "Ma'rifat al-Sahabah" (5787), and they made the questioner someone other than Abu Ishaq al-Sabi'i.
Details of the narration: Husayn bin Ayyash al-Raqqi made this clear in his narration in al-Nasa'i (8439), and likewise Abu Ghassan Malik bin Isma'il in Ibn Asakir (42/393). Both of them narrated it from Zuhayr and named the questioner as "Abd al-Rahman bin Khalid" (who is Ibn al-Walid al-Makhzumi). So what is "preserved" in Zuhayr's narration is that the questioner was Abd al-Rahman bin Khalid, not Abu Ishaq al-Sabi'i. This makes clear that the author (al-Hakim) here conflated Zuhayr's narration with that of Sharik al-Nakha'i, and in fact cited Sharik's narration, not Zuhayr's.

Technical note / Defect ('illah): Zayd bin Abi Unaysah contradicted the students of Abu Ishaq, in al-Nasa'i (8440). He narrated it from Abu Ishaq, from Khalid bin Qutham bin al-Abbas, that he was asked …; so he left the questioner unnamed and made the one questioned Khalid bin Qutham. But the chain up to Zayd contains a weak narrator. The "preserved" narration is that of Sharik and Qays bin al-Rabi', because Sharik heard from Abu Ishaq early on, while Zuhayr bin Mu'awiyah heard from him at the end of his life, when he had grown old.

Details of the narration: In a hadith of Ali bin Abi Talib himself, in al-Nasa'i (8397) through the route of Rabi'ah bin Najidh, it comes that a man said to Ali: O Commander of the Faithful, how did you become the heir of your cousin rather than your uncle? He said: The Messenger of Allah (peace and blessings be upon him) gathered Banu Abd al-Muttalib; then he mentioned the story of preparing food for them, and the Prophet's (peace and blessings be upon him) words: "Which of you will pledge to me that he will be my brother, my companion and my heir?" No one stood up, so I stood up, though I was the youngest of them. He said: "Sit down." He said it three times, and each time I stood up and he said: "Sit down", until on the third time he struck his hand upon my hand. Then (Ali) said: "That is how I became the heir of my cousin rather than my uncle." This narration is also in Ahmad (2/1371), but without mention of inheritance.
Grading: Its chain has "layyin" (softness/weakness). There is unknownness about Rabi'ah bin Najidh, and al-Dhahabi in "Mizan al-I'tidal" regarded this report of his as munkar.