Chapters 46-51 of Jeremiah are a collection of oracles against the nations.
Chapter 46 addresses the Egyptians. They will not fare well against the Babylonians. YHWH will offer them as a sacrifice (v. 10)! Egypt is described in animal imagery; Babylon in insect images:
Egypt is a beautiful heifer,
but a gadfly is coming
against her from the north.
Egypt's destruction will not be permanent. Verse 26 states that Egypt will be inhabited again one day. The chapter ends with a note that "Jacob" will suffer only limited punishment (vv. 27-28).
Chapter 47 is a short oracle against the Philistines. They are finally to be destroyed completely. Verses 6-7 are addressed to YHWH's sword which will not rest until it has attacked the Philistine city Ashkelon.
Chapter 48 is addressed to Moab. This chapter closely parallels Isaiah 15-16. The destruction of Moab is described city by city. Verse 10 curses those, Babylonians I should think, who do not take part in the destruction. Verses 11-12 use an analogy of wine.
Moab has been at rest from youth,
like wine left on its dregs,
not poured from one jar to another—
she has not gone into exile.
So she tastes as she did,
and her aroma is unchanged.
But days are coming,"
declares the Lord,
"when I will send men who pour from pitchers,
and they will pour her out;
they will empty her pitchers
and smash her jars."
Like Egypt, Moab will one day be restored:
"Yet I will restore the fortunes of Moab
in days to come,"
declares the Lord.
Next: Jeremiah 49-50