Nobara's current kernel supports Polaris and higher out of the box. This means your RX 400 and higher series.
AMD Southern Islands and Sea Islands cards are NOT supported because they have power management issues when used with the amdgpu driver.
Please note that OpenCL/ROCm support is limited to AMD's ROCm hardware compatibility matrix for the version shipped:
https://rocm.docs.amd.com/en/latest/compatibility/compatibility-matrix.html