Worse performance after enabling Nanite?

Converting a simple project of mine to UE5 (it only had some static meshes in the project), and enabled Nanite to see if I would get a performance gain.
But to my surprise I actually lost A LOT of FPS, I went from 60FPS to 14 FPS, I tweaked the Nanite Precision a little bit but it didn’t do much.

Don’t know if this is a bug or that i’m doing something wrong, anyway my meshes (walls, ceiling and floor etc.) are about 150-200K a piece in triangles without Nanite. Maybe they’re too low in tris count for Nanite to work, but than again why would the FPS decrease so much?

Before enabling nanite

After enabling nanite


I’m also losing fps really bad. not sure why


I had same problem just try to reduce lights in level

fren, i only had two lamps in the scene