Or HaChaim on Genesis 47:6/אור החיים על בראשית מ״ז:ו׳

1 במיטב הארץ…ישבו בארץ גשן, "they shall dwell in the land of Goshen in the best part of the country." Pharaoh was careful not to say only: "in the best part of the land," seeing that Joseph had indicated that he preferred that the brothers should live in the province of Goshen. If Pharaoh were not to confirm this specifically, Joseph might think that he did not want them to reside in Goshen. If, on the other hand, he were to say only that the brothers should reside in Goshen without adding the words "in the best part of the land," Joseph might feel that Pharaoh only assigned the inferior part of the province of Goshen to them. To avoid any misunderstanding, Pharaoh spelled out that the brothers should reside in the best part of the land of Goshen. Verse eleven then confirms that this is indeed what happened, that the land around Ramses was considered the best part of Goshen.

2It is also possible to understand the whole verse as a choice offered by Pharaoh. The brothers were welcome to reside in the best part of the land of Egypt; if, however, for whatever reason they preferred to settle in the province of Goshen, this too was acceptable to Pharaoh.