Hi, If you are tyring to find out which class has been assinged to which node (on console) then the better way to navigate your node. You can find all the nodes in overview tab. As soon as you click on nodes you can see class tab which will tell you the list of classes tagged with that particular node.
I know this is not the exact solution if you are willing to find the list of nodes tagged with any particular class. However you can achieve this using mco (mcollective command) and query your infra using Host filters Please find the details here.