emerge --search $MY_PACKAGE is not working well

Question

I could search a certain program (ex:htop) by emerge in Gentoo linux.

$ emerge --search sys-process/htop
[ Results for search key : sys-process/htop ]
Searching...
*  sys-process/htop
      Latest version available: 1.0.2-r1
      Latest version installed: [ Not Installed ]
      Size of files: 380 KiB
      Homepage:      http://htop.sourceforge.net
      Description:   interactive process viewer
      License:       BSD GPL-2
[ Applications found : 1 ]

But I can't search or install other programs (such as Nvidia driver)

$ emerge --search x11-drivers/nvidia-drivers
[ Results for search key : x11-drivers/nvidia-drivers ]
Searching...
[ Applications found : 0 ]

What is wrong?

Answer 1

If I run the searches i get the following results:

hydra ~ # emerge --search x11-drivers/nvidia-drivers
[ Results for search key : x11-drivers/nvidia-drivers ]
Searching...

*  x11-drivers/nvidia-drivers
      Latest version available: 455.45.01-r1
      Latest version installed: [ Not Installed ]
      Size of files: 180.214 KiB
      Homepage:      https://www.nvidia.com/Download/Find.aspx
      Description:   NVIDIA Accelerated Graphics Driver
      License:       GPL-2 NVIDIA-r2

[ Applications found : 1 ]

hydra ~ # emerge --search sys-process/htop
[ Results for search key : sys-process/htop ]
Searching...

*  sys-process/htop
      Latest version available: 3.0.2
      Latest version installed: 3.0.2
      Size of files: 173 KiB
      Homepage:      https://htop.dev/ https://github.com/htop-dev/htop
      Description:   interactive process viewer
      License:       BSD GPL-2

[ Applications found : 1 ]

Could you check if your portage tree is up to date? And what architecture are you using? x86_64?

emerge --sync