https://wccftech.com/fallout-76-mod-for-fallout-4/

A freshly released Fallout 76 mod for Fallout 4 allows players to experience Bethesda’s upcoming prequel ahead of its release this year.

Truth be told, this is not the full Fallout 76 experience, but players will be able to get a taste of the next Fallout installment.  The mod has no dependencies on extenders or expansions and does not change any base game scripts, assets or objects as it’s 100% pure new Creation Kit forms and wrapper scripts.