What line number of the 740NP are you asking about? Line 29 (liability) or Line 30 (withholding)?
State tax liability is not reported on a W2. The W2 only shows how much was withheld (Line 30), and the liability can be lower or greater than what is withheld.
Only states with a flat(ish) tax (like perhaps Pennsylvania) could withhold the exact amount of your liability.
