(1) In determining the tax liability of a nonresident partner of any partnership, there shall be included in Nebraska adjusted gross income only that part derived from or connected with sources in this state of the partner's distributive share of items of partnership income, gain, loss, and deduction entering into his or her federal taxable income, as such part is determined under rules and regulations prescribed by the Tax Commissioner in accordance with the general rules in section 77-2733.

(2) In determining the sources of a nonresident partner's income, no effect shall be given to a provision in the partnership agreement which:

(a) Characterizes payments to the partner as being for services or for the use of capital, or allocated to the partner, as income or gain from sources outside this state, a greater proportion of his or her distributive share of partnership income or gain than the ratio of partnership income or gain from sources outside this state to partnership income or gain from all sources, except as authorized in subsection (4) of this section; or

(b) Allocates to the partner a greater proportion of a partnership item of loss or deduction connected with sources in this state than his or her proportionate share, for federal income tax purposes, of partnership loss or deduction generally, except as authorized in subsection (4) of this section.

(3) Any modification described in subsection (1) of section 77-2716 which relates to an item of partnership income, gain, loss, or deduction, shall be made in accordance with the partner's distributive share, for federal income tax purposes of the item to which the modification relates, but limited to the portion of such item derived from or connected with sources in this state.

(4) The Tax Commissioner may, on application, authorize the use of such other methods of determining a nonresident partner's portion of partnership items derived from or connected with sources in this state, and the modifications related thereto, as may be appropriate and equitable, on such terms and conditions as he or she may require.

(5) The character of partnership items for a nonresident partner shall be determined under section 77-2725.