No, level instancing is not available right now. How to use level instancing in UEFN?
However you could create your own blueprints.
Create a level in the content browser by clicking on “new” > “level”. Open that level and go to the world settings > check “is playset” and select a category. After you save the leven, a new folder will appear in your content browser called “prefabs”. In that folder you can find the new level as prefab. Dag it into your original level and done. 
Note: When you place the prefab in a level it will not sync with the level. For that we need to wait for level instancing.
