Is there a way to assign a separate texture for specific 3D View? Like if I have some texture in material node, but want to see UV checker in viewport without changing material itself.
Assigning separate materials to a view port is not possible ( as far I know )
Alternative: With the Node Wrangler plugin you can press Ctrl + Shift + Click on a node, and it will change it to that specific node. So you can just add an image texture to your node an swap between them.
See: http://gregzaal.github.io/node-wrangler/ ( Emission Viewer )