Having the same issue thats listed in this post linked at the bottom, followed the comments suggestions but after looking into my max supported shader model on my Nvidia Geforce RTX 3080 (it supports 6.6)
so that shouldnt be the issue. just wanted to report im having this also and can reproduce in new projects, i also freshly installed windows 11 recently
steps to reproduce are the exact same as listed in the post below
1- New 3rd Person Project.
2- Select blue cube.
3- Open its mesh → Enable Nanite.
4- Create GeometryCollection for that blue cube.
5- GeometryCollection → Enable Nanite.
6- Blue cube disppears. *