Fallout 3 Mods on Xbox 360: Not Supported

You cannot install mods for Fallout 3 on Xbox 360.

Why:

• Closed Platform: Xbox 360 only runs digitally signed code. No user-created scripts, assets, or .esp/.esm plugins can load.
• No Mod Framework: Bethesda's Creation Kit/Mod Manager ecosystem is PC-only.
• DLC Only: The 360 got 5 official DLC packs (Operation: Anchorage, The Pitt, Broken Steel, Point Lookout, Mothership Zeta) via Xbox Live Marketplace—these are the only "extra content."

To Play With Mods:

• PC (Steam/GOG/Microsoft Store): Thousands of mods on Nexus Mods, Bethesda.net. Use Mod Organizer 2 or Vortex to manage.
• Fallout 3 GOTY on PC often < $5 on sale—best way to experience the game fully.

Note: Xbox One/Series X|S backward compatibility plays the base 360 version + DLC, but still no mod support (unlike Fallout 4 / Skyrim Special Edition which have Bethesda.net mods on console).