With chapter 30 we now begin a short (5 chapters) section of Jeremiah dealing with a promise of hope. God does not disown His people. He may punish them, kill them, and disinherit them, but He never disowns His people. The Lord will alternate in these chapters from a review of His people’s current condition (incurable, punished, devoured) to why (sin) to restoration. The nations God uses to punish His people will be destroyed for doing precisely what God has told them to do: inflict pain on His people.
There is no way for the nations to win. God is sovereign, and no matter how He treats His people, they are still His people and enjoy not only Most Favored Nation status, but Only Favored Nation status.