Rashi #1: Kasdim is not from Eretz Kena'an! Rather, you increased idols of Kasdim over those of Kena'anim, who were close to you, and you were already Mezanah with them.

Rashi citing Targum Yonasan: You increased your Zenus like Kasdimim, and are like Kena'anim who are immersed in idolatry, and increased your gods to join to the nation of Kena'an, to go in the ways of the Kasdim.

Rashi #2: Kena'an is a merchant, like "Kena'an b'Yado Moznei Mirmah" (Hoshe'a 12:8). Eretz Kasdim is called Eretz Socharim ? "va'Yvi'ehu El Eretz Kena'an b'Ir Rochelim Samo" (below, 17:4).

Radak #1: Some say that this is like me'Eretz (more than the land of) Kena'an ¹ .

Radak #2: Like the abominations of Eretz Kena'an that the Kena'anim did, that Hashem dispossessed them from in front of you. It says about Menasheh "mi'Kol Asher Asu ha'Emori Asher Lefanav" (Melachim II, 21:11). Your Zenus resembled Eretz Kena'an, when it was Eretz Kena'an ² . Kasdimah means El Kasdim ? you resembled [Eretz Kena'an and] Eretz Kasdim.

Malbim: This was until the days of Menasheh. Then, they did these acts constantly, and began to be Mezanah El Bnei Bavel. I.e. you increased your Zenus from Eretz Kena'an to Eretz Kasdim, to do with them the abominations of the Kena'ani.

Radak: Even after going in the ways of both [Kena'an and Kasdim], you were not satiated.

Malbim: They captured Menasheh, and brought him to Bavel.