i have this node setup acting as the displacement, what i would like to do is add a texture or a colour only where the displacement is being added on the object, i would like to make molten like cracks but i cant find the way to apply that colour only on the cracks
You can just add in a mix node, another principled shader and a color ramp.
Create a 2nd principled shader (this will be your lava).
Connect it with a mix shader, use a color ramp and have your displacement nodes connect to it.
Then on your color ramp adjust the flags to your liking.