I agree, find something that you really love to display in there.

It's so very ornate, it's hard to not consider something equally ornate.

I need to see some examples of your style . For me it would be closed off and a really nice piece of art on that wall. I think it gives off a really religious feel .

1. Tall vase of flowers.
2. Add to shelves in it and add a sign decor in it such as :- “HO” on the top shelf and “ME” on the lower one forming “Home”.
3. Wallpaper the niche and add a tall lantern.
4. Add a hook at its ceiling and hang decor

Look at the big end of this chart and put the largest bottle of champagne you can fit there to drink when we all go to hell in a handbasket.

A large figurine or vase that coordinates with the ornate mounding.

Ideally, you'd find a sculpture that fit perfectly. Otherwise, I'd go with a vase about the height of up to the trim, then something dry on top, peacock feathers, feathery grass.

Silverplate is generally quite affordable. You could probably get a silverplate jug for a reasonable price to use as the vase

I too have a niche and I have placed a statue of La Virgen de Guadalupe. It’s not a decor item for us because it’s in a private space and it reflects our Catholic faith. Find something that you like that is meaningful to you, but a lovely vase or piece of ceramic will also work. Good luck!

It’s lovely and unique! Do not close it off nor hang anything from the top. Get one large something (sculpture, vase, basket, etc.) to fill most of the space.