That, I do not know, to be honest. It really depends on the complexity of the shader and what it uses.
I'd look into seeing what the GLSL code is for the Blender nodes, as Godot uses a shader language very similar to GLSL. Then it should, in theory, just be a matter of translating the GLSL to Godot's GLSL, though in practice there may be differences that make this a little more challenging.
I know in Godot 4.0 there are plans for Godot to support GLSL directly, which would make the Blender shader porting process much easier.
https://twitter.com/reduzio/status/1252052089762693120
Also, GDQuest has a cartoon shader that may be of interest. It doesn't quite look like the Blender shader, but it looks similar:
https://twitter.com/NathanGDQuest/status/1290278747120304128