This error appears due to a missing reference to the imported .sopcinfo from previous project into the new workspace.
This problem is fixed starting with the Intel® Quartus® Prime Pro Edition software version 20.4.
To fix this, follow the next steps:
1. Import the eclipse project
o Import-> Nios® II Software Build Tools Project ---> Import Nios® II Software Build Tools Project
o Start NIOS® II and select work-space to 'software' folder
o Import project code. Select folder for this, and make sure name of project matches folder.
o Import BSP files. Select folder for this and again make sure name matches folder.
2. Edit the make file (variable name SOPC_FILE=) and settings.bsp file (Tag name SopcDesignFile=) such that we are pointing to the correct directory of .sopcinfo file.