This is the more correct of the two grammatical analyses.
There is a third analysis: that (man) occupies a nominative position as the subject of a nominal sentence, meaning: “As for the believers who follow you, Allah is sufficient for them.”
There is a fourth analysis, which is incorrect in meaning (1): namely (2), that (man) occupies a nominative position through coordination with the name of Allah, giving the meaning: “Allah and your followers are sufficient for you.” Although some have advanced this interpretation (3), it is entirely mistaken, and the verse cannot legitimately be understood in this way. For Allah alone is sufficient and meets one’s needs, just as reliance, piety, and worship must be directed to Him alone. Allah Most High says (4):
“But if they intend to deceive you, Allah is sufficient for you. It is He who supported you with His help and with the believers.” [Al-Anfāl: 62]
He thus distinguishes between sufficiency and support: He makes sufficiency His alone, while providing support through His help and His servants (5).
And He, glorified be He, praised those of His servants who uphold monotheism (6) for affirming that He alone is sufficient for them,