Fallout 3 dlc onto my Xbox one (s)

To get your DLC back (if you already own it digitally), please go to My Games and Apps > Games > Push START (3 lines button) on your game > Manage game > Your DLC is there to download.

If you have a game disc with the DLC on them you can't use that DLC and put that on your Xbox one: you will have to purchase that DLC again for use on Xbox one.

If you read the issues with Fallout 3 back compat, only the standard version did not work with the DLC. You need to insert the disc with the dlc in, and that should install the game and the dlc as well.

Taken from
here

Fallout 3: You will only be able to play disc based DLC for Fallout 3 if you also own the digital version of the game. Disc based DLC includes the Broken Steel and Point Lookout disc and the Operation Anchorage and The Pitt disc.
This restriction does not apply to the Game of the Year Edition.

If you have the DLC's on disc you will have to buy them again. Those won't work

I have a fallout 3 problem myself. I have fallout 3 GOTY, my game disc does not read well on the one but the 360 it reads fine. the dlc disc of fallout 3 is fine and can read on the one.

Because I preordered fallout 4 I got fallout 3 game itself for download but no dlc with it so I put in the dlc disc and the console installed the dlc no problem. I run the game and check downloads and none of the dlc shows up at all not even when I load
the game but it's on my game manager as installed...

While my personal favorite is Fallout 2, I'll go with NV. Better story, bigger quest variety, improved gameplay (had a hard time going back to 3 after playing NV), character's eyes don't look dead, DLC is just as good as Fallout 3's DLCs, as in they both
have their good and bad. One key aspect that everyone seems to prefer in one game is exploration. I can definitely see how one would prefer exploring in Fallout 3 because of the constant action, but personally I like them both the same in this aspect.