"If there is no income during the nonresident period you may not need the 1040NR at all." I disagree.

You file the tax return using the form according to your status at the end of the year, which is form 1040-NR in this case. The income and deductions during the resident period should be transferred to form 1040-NR.

For this case, you do not file form 1040 per se, you can use it as an attachment but you can create another document as the attachment as long as it has the information needed.