Hi!
Is there any way to change texture for shader material via script ?
Shader texture
Yes, you would get the material first in a variable like this:
var mat = your_mesh_instance.mesh.surface_get_material(0)
mat.albedo_texture = some_texture
https://docs.godotengine.org/en/stable/classes/class_basematerial3d.html#class-basematerial3d