There is a hadith which says emigration has not stopped as long as disblievers are being fought (it’s in sunan nasai 4172). How can we reconciled that with the hadith where the Prophet (phub) says emigration has stopped.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Dear brother, if you mean the Hadeeth reported by Al-Bukhari: “There is no migration after the Conquest (of Makkah).”; then it means that there is no migration from Makkah to Madeenah because Makkah has become a Land of Islam.

Ibn Hajar said in Fat'h al-Baari:

“The Prophet’s saying: “There is no migration after the Conquest”, means the conquest of Makkah. Al-Khattaabi and others said: “Migration was an obligation at the beginning of Islam for whoever becomes a Muslim because of the small number of the Muslims in Madeenah and their need to get together. However, when Allah gave victory [to the believers] over Makkah, people entered the religion of Allah in crowds so the obligation of migration to Madeenah was waived off, and what remained is the obligation of Jihad and intention on whoever has undertaken Jihad or was attacked by an enemy.” [End of quote]

The migration that was denied in the Hadeeth is the migration from Makkah to Madeenah, as this kind of migration is irrelevant after Makkah has become the Land of Islam after the Conquest.

As for the migration from the Land of disbelief to the Land of Islam, then this kind of migration still remains, as in the Hadeeth: "Migration does not cease as long as the enemy is being fought.” [An-Nasaa'i, and Ibn Hibbaan classified it as authentic]

Another Hadeeth reads: “Migration will not come to an end till repentance comes to an end, and repentance will not come to an end till the sun rises in the place where it sets.” [Abu Daawood and others]

Ibn Hajar said in Fat'h al-Baari:

“Ibn ‘Umar explained the meaning in the narration reported by al-Isma’eeli and attributed to the Prophet with the wording: “Migration has ceased after the Conquest but migration does not stop as long as the disbelievers are being fought.”; meaning that as long as there is a Land of disbelief in this world, migration is obligatory from it for whoever has embraced Islam and fears to be tempted in his religion.” [End of quote]

Allah knows best.