Why did our tax due amount increase singifcantly after reporting income on a 1099-MISC?

[SweetieJean]

Was it for work performed? You owe approx. 15% self-employment tax, as well as regular income taxes, on that 1099-MISC.

And any increase in income can lower some deductions (such as Medical) and credits (such as EIC).

[donandpat15]

Even if it's just a payment for board of directors?

[SweetieJean]

Is there an amount in Box 3 or in Box 7 of the 1099-MISC?

[SweetieJean]

Per IRS:
You must report directors' fees and other remuneration, including payments made after retirement, on Form 1099-MISC in the year paid. Report them in box 7.