Either, 1. Nineveh, which is called a great city, Jonah 3:3, Jonah 4:11; and indeed was so, being sixty miles in compass. Thus it is a trajection, and the relative is referred to the remoter noun, as sometimes is done, though this seems to be a little forced. Or, 2. Resen; so the meaning is, though this city be much inferior to Nineveh, yet this also, if compared with most others, is a great city.
Related Commentaries of Genesis 10:12
Genesis 10:12
12 And Resen between Nineveh and Calah: the same is a great city.