First, remember that the conductance G plays the role of a reciprocal resistance. Thus a 4 S conductor has a resistance of 0.25 ohm. Also Ohm's law V=IR may be written as I=VG, a form which is well adapted to nodal analysis.
There are three non-trivial nodes; I choose labels V1, V2, and V3 from left to right.
The nodal equation for the node on the far left is then:
2 + (V1 - V2) + (V1 - V3).2 = 0.
Write down the remaining two nodal equations and solve for V2.
You may find a Linear Algebra Solver to be useful in finding the final answer.