When I was experimenting with my new printer, I suddenly realized I could print a table-top sized version of one of the fantastic Modern Christmas Trees (see the attached pic showing one of the real, 8-foot-tall ones)! So I designed the rings, and altered a Saarinen tulip chair base to make the stand.

These files will allow you to print a tiny tree! It's very cute on a desktop or mantelpiece.

Please note that the pointy top of the stand will need to be glued on for now; I need to adjust the size some more to avoid that. I also intend to change the star to something a bit more "atomic." Eventually.

You will need to purchase some bead chain to put it together; it's pretty cheap at a craft store. Count the beads on the chain for each level to make sure that the rings will hang evenly. I also bought some clamshell bead tips SIMILAR to  those at https://www.firemountaingems.com/itemdetails/h202164fn -- I used these on the chain underneath each ring to keep it from sliding down. There may be better ways to do this (hot glue would be pretty simple), but it worked OK!

As far as ornaments go -- it is unlikely you will find actual ornaments small enough. Beads are a great option! If you have some wire around, you can make little ornament hooks in an s-shape for them!

I recommend trying this with some translucent filament -- that will look really cool! :)