First you need to found nobody users files than change it to cPanel main user name so that you can change/edit the files without any problem.But its difficult to check ownership one by one for all files in that case you can use following single command
root@admin[/home/test]#find ./ -user “nobody” | xargs chown test.test
In above command find will check all files owned by nobody user and after that it chown will change the ownership to test.test where test is cPanel user name
