is there a schedule F in your Illinois return? the excludable amount carries to schedule M line 23.
If gain subject to the valuation limitation was reported on any of
the following forms or schedules, you must attach copies of them
to your Schedule F: federal Form 1040 or 1040-SR, Schedule D;
federal Form 4797; federal Form 6252; federal Form 8949; Illinois
Schedule K-1-P, Partner’s or Shareholder’s Share of Income,
Deductions, Credits, and Recapture; and Illinois Schedule K-1-T,
Beneficiary’s Share of Income and Deductions.
For installment sales, see instructions on the back of
Schedule F.
these additional forms can not be e-filed so you'll have to mail in your Illinois return with schedule F and all other required federal forms.
