Which border turned to the west?
Bi'ur ha'Gra: The [southern] border turned [from the Yarden] to the west, like the verse says that it touched Zevulun from the south.
Malbim: In the north, the border turned to the west.
Why does it say Aznos Tavor? Above (12), it says Kislos Tavor!
Rashi (12): Kislos Tavor is on the incline, in the middle, like flanks of an animal. Aznos Tavor is close to the peak.
Radak: They are different names for the same place, for a reason that they knew.
Where is Chukokah?
Bi'ur ha'Gra: It is the other side of Aznos Tavor [on Naftoli's southern border].
Malbim: It is at the north of Eretz Yisrael. Naftoli's border turned north after going west from the northern end (source) of the Yarden.
Where did Naftoli border the eastern Shevatim?
Metzudas David, Malbim: Naftoli met Yehudah at the end of the Yarden (where it enters Yam ha'Melach). It also met the other Shevatim whose borders go [almost] to the Yarden (Yosef, Yisachar and Binyamin); the Chidush is that it met Yehudah, which was in the south.
Where did Naftoli border Asher and Zevulun?
Metzudas David: The south of Zevulun was the north of Naftoli. The west of Naftoli was the east of Asher.
Bi'ur ha'Gra: Its southern border encountered Zevulun; its western border encountered Asher.
Malbim: The western border of Naftoli bordered a strip that extended from Asher, east of Zevulun, to the north of Eretz Yisrael. The strip did not reach the end of Eretz Yisrael, for a strip from Naftoli was north of it, and the south of the strip was the northern border of Zevulun.