I have a couple of new nucs (3-4 days), when checking today to see if the new queens were released and accepted (they were) I found their populations very sparse and lots of chilled capped brood. With little free time my "quick fix" was to swap out the location of the 2 nucs with that of a strong split from about 6 weeks ago (now about 12+ frames)

Have I thrown "good money after bad?" Am I just weakening a hive in hopeless effort to pull these back from the brink?

Back story:
4 days ago I pulled 4 frames mostly capped brood, 2 frames of pollen and 2 of honey from several different hives. Shook off all the bees as I took them, then placed in an empty box over an excluder on a strong hive overnight. Next morning they were well/completely covered. Moved them into 5 frame nuc boxes with an empty frame, and added caged queen at the end of the day. All pretty standard from what I read.
But I was a bit worried from the start, as I had wanted more open brood in the mix, and the hive I put the frames over to repopulate had very little open brood in itself. So I assume the bees I moved out were older and went right back to the parent hive (same yard).
When I checked today what I saw was lots of uncapped chilled pupa on one side of each brood frame, the faces/seam between them appeared OK and I assume they were able to cover those faces at least. So I should be getting a frame worth of bees out of them soon...I hope.

Live and learn, where else did I go wrong in this operation?