A basic question about this nodal analysis
The voltage at the node to the left of R3 is V1, hence current away from the V2 node and through R3 is (V2-V1)/R3. Note that R2 and R3 are NOT in series as there is another resistor (R1), and a current generator connected to their junction.

Similarly the current through the capacitor and away from the V2 node is (V2-0)/-j

The sum of the above two currents must equal the current flowing towards the V2 node, which is 4 Amps from the current generator.

Note that the two blobs of solder between R1 and R3 do not constitute two nodes - there is only one node betwen these two resistors and that is V1