Here's what I found on NJ tax return which confirms there cannot be a negative number FYI
Reporting Losses. If you have a net loss in any category of
income, remember the following:
• You cannot report a loss on your NJ-1040 (e.g., in parentheses or as a negative number);
• You can net losses with gains in the same category of
income. For example, you can subtract gambling losses
from gambling winnings during the tax year;
• You cannot apply a net loss in one category of income
against income or gains in a different category on your
NJ-1040. For example, you cannot subtract gambling
losses from your wages;
• If you have a net loss in any income category, make no
entry on that line of your NJ-1040. Do not enter zero. Do
not enter the amount of the loss in parentheses or as a
negative number;
• No carryback or carryover of losses is allowed when reporting income on your NJ-1040.
