I’m guessing you installed content with some method other than JetPack/SDK Manager. nvidia-smi is for PCI-based GPUs, but Jetson GPUs are directly integrated with the memory controller. That software (and drivers) will fail with non-PCI GPUs.
You’ll need to remove anything which was not for the Jetson, and add via JetPack/SDKM instead (use the release currently installed).
I will recommend flashing and reinstalling if you don’t need what is present. However, here are some general tips:
To find out the full path of a program, e.g., nvidia-smi: which nvidia-smi
To search for the package owning a program: dpkg -S /usr/bin/nvidia-smi
To both find and search in one command (remove the backslash “\”, I have those to escape the forum’s use of the single backquote and it won’t let me type it in correctly…basically the first “which nvidia-smi” surrounded by single backquote):
dpkg -S \`which nvidia-smi\`
To remove a package, for example “nvidia-utils-450” (which happens to be a desktop version and not intended for a Jetson): sudo apt remove nvidia-utils-450
To see which L4T release runs on your Jetson: head -n 1 /etc/nv_tegra_release
To find the correct software for installing to a Jetson (including flash, but you can uncheck everything except for the package you want to install to the Jetson): https://developer.nvidia.com/linux-tegra
(each L4T release is tied to a single JetPack/SDKM release)
Additional note for when you’ll have clean up as advised by @linuxdev :
You can get similar information as from nvidia-smi from other tools with Jetson;
Get GPU capabilities: you can get that from deviceQuery. Just build as root the sample in /usr/local/cuda/samples/1_Utilities/deviceQuery and run it.
Get GPU usage and temperature : You may use tool tegrastats. GPU is referred as GR3D, you would see usage and current clock frequency. For temperature, you would further see something like: GPU@40.875C
For memory usage, Jetsons have an iGPU sharing physical memory with the system.