There is no way to have multiple shaders on one node as a shader is just a set of instructions for how to draw an object. You can't have multiple conflicting sets of instructions.
With 3D materials however, you can conceptually have multiple shaders by running shaders one-after-the-other. This is done by selecting a second shader to be run on "Next pass".
With 2D materials, this is not possible as it would just render the second sprite on top of the first and you wouldnt see the effects of the first shader.