Mixing 2 different materials

There’s a special node in the Shader category called Material Mixer, it can be used to bake 2 procedural or PBR materials using a texture or procedural mask.
At the moment the connections for this node have to be made manually. You can plug image texture nodes or any baking output of the procedural materials of the library.

To bring a procedural material, add it to the scene, select the nodegroup of that material, copy it and paste it on the material where you want to make the mixing.